Liquid-crystal media and light modulation element
AssigneeMerck Patent GmbH
InventorsDong-Mee Song, Hyun-Woo Bae, Jung-Min Lee, Yong-Kuk Yun
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Abstract
The present invention relates to liquid crystalline (LC) medium, to a method of its production and to the use of such LC media in polymer network liquid crystalline (PNLC) light modulation elements operated in the normally transparent mode. Furthermore, the present invention relates to such light modulation elements, as such, to the use of such light modulation elements as light shutters for transparent OLED displays, to the use of such light modulation elements in smart windows, and to a method of production of such light modulation elements according to the present invention.
Claims17
A LC medium comprising, one or more non-polymerisable LC compounds, one or more polymerisable LC compounds, one or more carbazole oxime ester photoinitiators, and one or more dichroic dyes, wherein one or more of the carbazole oxime ester photoinitiators are selected from the group of compounds of formula CO-1,
- wherein
- L31 to L33 each and independently denotes H, alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms;
- F, Cl, CN, NO2, OCN, SCN, or mono- oligo- or polyfluorinated alkyl or alkoxy with 1 to 4 C atoms;
- or —(X31—Sp31-A31),
- X31 denotes —O—, —S—CO—, —COO—, —OCO—, —O—COO—, —CO—NRxx—, —NRxx—CO—, —NRxx—CO—NRyy— or a single bond,
- Rxx and Ryy each, independently of one another, denote H or alkyl having 1 to 12 C atoms,
- Sp31 is a spacer group or a single bond,
- A31 denotes each and independently an aryl, heteroaryl, non-aromatic alicyclic and heterocyclic group, optionally having one or more substituents, which are selected from the group comprising silyl, sulfo, sulfonyl, formyl, amine, inline, nitrile, mercapto, nitro, halogen, C1-12 alkyl, C6-12 aryl, C1-12 alkoxy, hydroxyl, or combinations of these groups, and
- R32 to R34 each, independently of one another, denote H or alkyl having 1 to 12 C atoms.
A LC medium comprising, one or more non-polymerisable LC compounds, one or more polymerizable LC compounds, one or more carbazole oxime ester photoinitiators, and one or more dichroic dyes, wherein
- A) said one or more non-polymerizable LC compounds are selected from the group of the compounds of the formulae I-1, I-2, I-3 and I-4,
- in which
- R2A denotes H, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF2O—, —CH═CH—,
- —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen,
- L1 and L2 each, independently of one another, denote F, Cl, CF3 or CHF2,
- Z2 and Z2′ each, independently of one another, denote a single bond, —CH2CH2—, —CH═CH—, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —COO—, —OCO—, —C2F4—, —CF═CF— or —CH═CHCH2O—,
- p denotes 0, 1 or 2,
- q denotes 0 or 1,
- (O)CvH2v+1 denotes OCvH2v+1 or CvH2v+1, and
- v denotes 1 to 6;
- and
- B) said one or more dichroic dyes are selected from the group of compounds of formula D,
- wherein,
- to
- are at each occurrence, identically or differently, selected from
- and, in case i is 2 or more, the terminal one of group
- may also be
- and, in case j is 2 or more, the terminal one of group
- may also be
- Z11 and Z12 are, independently of each other, —N═N—, —OCO— or COO—,
- R11 and R12 are, independently of each other, alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl, alkylaminyl, dialkylaminyl, alkylcarbonyl, alkyloxycarbonyl, alkylcarbonyloxy, alkyloxycarbonyloxy or alkylcyclohexylalkyl, and
- i and j are independently of each other 1, 2, 3 or 4.
Dependencies are inferred from the claim text.