Patent Application
20250154412
This is a U.S. national application filed under 35 U.S.C. § 111, claiming benefit and priority under 35 U.S.C. § 119(a) of and to European Application No. 23208564.7, filed Nov. 8, 2023, the contents of which are incorporated herein by reference in their entirety and for all purposes.
The present invention relates to a compound, a liquid-crystalline medium comprising said compound, and to high-frequency components comprising the medium, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tuneable filters, tuneable metamaterial structures, and electronic beam steering antennas (e.g., phased array antennas), and to devices comprising said components. The invention further relates to an optical component comprising said liquid-crystalline medium, operable in the infrared region (IR) of the electromagnetic spectrum. The invention further relates to the use of said LC medium in the infrared region and to devices comprising said optical component.
Liquid-crystalline media have been used for many years in electro-optical displays (liquid crystal displays: LCDs) in order to display information. More recently, however, liquid-crystalline media have also been proposed for use in components for microwave technology, such as, for example, in DE 10 2004 029 429 A and in JP 2005-120208 (A).
A. Gaebler, F. Goelden, S. Müller, A. Penirschke and R. Jakoby “Direct Simulation of Material Permittivities using an Eigen-Susceptibility Formulation of the Vector Variational Approach”, 12MTC 2009—International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), pp. 463-467, describe the corresponding properties of the known liquid-crystal mixture E7 (Merck KGaA, Germany).
DE 10 2004 029 429 A describes the use of liquid-crystal media in microwave technology, inter alia in phase shifters. Therein, liquid-crystalline media with respect to their properties in the corresponding frequency range have been discussed and liquid-crystalline media based on mixtures of mostly aromatic nitriles and isothiocyanates have been shown.
Compositions available for the use in microwave applications are still afflicted with several disadvantages. It is required to improve these media with respect to their general physical properties, the shelf life and the stability under operation in a device. In view of the multitude of different parameters which have to be considered and improved for the development of liquid crystalline media for microwave application it is desirable to have a broader range of possible mixture components for the development of such liquid-crystalline media.
An object of the present invention is to provide a compound for the use in liquid crystalline media with improved properties relevant for the application in the microwave range of the electromagnetic spectrum.
To solve the problem, a compound of formula AN defined below is provided and a liquid crystalline medium comprising the compound.
The present invention relates to a compound of the formula AN
identically or differently, denote 1,4-phenylene, 2,6-naphthylene, 1,2-dihydronaphthalene-3,7-diyl, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by RL, benzo[1,2-b:4,5-b′]dithiophene-2,5-diyl, thiophene-2,5-diyl, or thieno[3,2-b]thiophene-2,5-diyl
alternatively denotes 1,4-cyclohexylene, 1,4-cyclohexenylene, bicyclo[1.1.1]pentane-1,3-diyl, 4,4′-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, or spiro[3.3]heptane-2,6-diyl, in which one or more non-adjacent CH2 groups may be replaced by —O— and/or —S— and in which one or more H atoms may be replaced by F, and
Preferred embodiments of the present invention are subject matter of the dependent claims or can also be taken from the description.
Structurally related mesogenic compounds with a cyanoethynyl terminal group are known from prior art, as shown for example in JP 60-019 756 A2, DE 32 46 440 A1, DE 19831093 A1, WO 2018/166999 A1, CN 115678573 A and U.S. Pat. No. 11,492,551 B2.
Surprisingly, it has been found that it is possible to achieve liquid-crystalline media having excellent stability and at the same time a high dielectric anisotropy, suitably fast switching times, a suitable, nematic phase range, high tunability and low dielectric loss in the microwave range of the electromagnetic spectrum by using compounds of formula AN in liquid-crystalline media.
In particular, the media according to the invention comprising the compound according to the invention are distinguished by an improved figure-of-merit η due to a higher tunability τ and lower dielectric loss.
The media according to the present invention are further distinguished by a high clearing temperature, a broad nematic phase range and excellent low-temperature stability (LTS). As a result, devices containing the media are operable under extreme temperature conditions.
The media are further distinguished by high values of the dielectric anisotropy and low rotational viscosities. As a result, the threshold voltage, i.e. the minimum voltage at which a device is switchable, is very low. A low operating voltage and low threshold voltage is desired in order to enable a device having improved switching characteristics and high energy efficiency. Low rotational viscosities enable fast switching of the devices according to the invention.
These properties as a whole make the media particularly suitable for use in components and devices for high-frequency technology and applications in the microwave range, in particular devices for shifting the phase of microwaves, tuneable filters, tuneable metamaterial structures, and electronic beam steering antennas (e.g. phased array antennas).
According to another aspect of the present invention there is thus provided a component and a device comprising said component, both operable in the microwave region of the electromagnetic spectrum. Preferred components are phase shifters, varactors, wireless and radio wave antenna arrays, matching circuits and adaptive filters.
The medium according to the invention is likewise suitable for use in the infrared region of the electromagnetic spectrum.
The invention thus further relates to the use of the medium defined above in the infrared region of the electromagnetic spectrum, preferably in the A-band, and/or B-band and/or C-band, for phase modulation of said infrared light.
According to another aspect of the present invention there is provided an optical component comprising the liquid crystal medium according to the invention sandwiched between a pair of substrates.
The invention further relates to a device comprising the optical component according to the invention. Preferred devices are infrared imagers, wavelength selective switches, LCOS-SLM, LIDAR systems, wavelength-division multiplexing (WDM) systems, reconfigurable optical add-drop multiplexer (ROADM), and nonmechanical beam steering, e.g. steerable Electro Evanescent Optical Refraction (SEEOR) prism as published in the article P. McManamon, 2006, “Agile Nonmechanical Beam Steering,” Opt. Photon. News 17 (3): 24-29.
According to another aspect of the present invention there is provided a method of spatially modulating infrared light, the method comprising,
According to another aspect of the present invention there is provided a method of manufacturing an optical phase modulator, comprising at least the steps of
The optical component according to the invention is distinguished by excellent operational stability when exposed to the environment because of high clearing temperature, broad nematic phase range and excellent low-temperature stability (LTS) of the liquid crystal medium used therein. As a result, the component and devices containing the component are operable under extreme temperature conditions.
The media used in the component according to the invention are distinguished by high values of the dielectric anisotropy and low rotational viscosities. As a result, the threshold voltage, i.e. the minimum voltage at which a device is switchable, is very low. A low operating voltage and low threshold voltage is desired in order to enable a device having improved switching characteristics and high energy efficiency. Low rotational viscosities enable fast switching of the components and devices according to the invention.
Herein, “high-frequency technology” means applications of electromagnetic radiation having frequencies in the range of from 1 MHz to 1 THz, preferably from 1 GHz to 500 GHz, more preferably 2 GHz to 300 GHz, particularly preferably from about 5 GHZ to 150 GHz.
As used herein, infrared region of the electromagnetic spectrum is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 0.75 μm to 1000 μm.
As used herein, infrared A (IR-A) is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 0.75 μm to 1.4 μm.
As used herein, infrared B (IR-B) is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 1.4 μm to 3 μm.
As used herein, infrared C (IR-C) is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 3 μm to 1000 μm.
Preferably, the optical component according to the invention operates at a wavelength in the range of from 750 nm to 2500 nm, in particular from 1530 nm to 1565 nm.
A very preferred light source for applications according to the invention is an IR laser emitting light with a wavelength of 1.55 μm or an IR laser emitting light with a wavelength of 905 nm.
As used herein, halogen is F, Cl, Br or I, preferably F or Cl, particularly preferably F.
Herein, alkyl is straight-chain or branched or cyclic and has 1 to 12 C atoms, is preferably straight-chain and has, unless indicated otherwise, 1, 2, 3, 4, 5, 6 or 7 C atoms and is accordingly preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl.
Herein, branched alkyl is preferably isopropyl, s-butyl, isobutyl, isopentyl, 2-methylbutyl, 2-methylhexyl or 2-ethylhexyl.
As used herein, cyclic alkyl is taken to mean straight-chain or branched alkyl or alkenyl having up to 12 C atoms, preferably alkyl having 1 to 7 C atoms, in which a group CH2 is replaced with a carbocyclic ring having 3 to 5 C atoms, very preferably selected from the group consisting of cyclopropylalkyl, cyclobutylalkyl, cyclopentylalkyl and cyclopentenylalkyl.
Herein, an alkoxy radical is straight-chain or branched and contains 1 to 15 C atoms. It is preferably straight-chain and has, unless indicated otherwise, 1, 2, 3, 4, 5, 6 or 7 C atoms and is accordingly preferably methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy or n-heptoxy.
Herein, an alkenyl radical is preferably an alkenyl radical having 2 to 12 C atoms, which is straight-chain or branched and contains at least one C—C double bond. It is preferably straight-chain and has 2 to 7 C atoms. Accordingly, it is preferably vinyl, prop-1- or -2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-, -4-, -5- or -6-enyl. If the two C atoms of the C═C double bond are substituted, the alkenyl radical can be in the form of E and/or Z isomer (trans/cis). In general, the respective E isomers are preferred. Of the alkenyl radicals, prop-2-enyl, but-2-and-3-enyl, and pent-3-and-4-enyl are particularly preferred.
Herein, alkynyl is taken to mean an alkynyl radical having 2 to 12 C atoms, which is straight-chain or branched and contains at least one C—C triple bond. Terminal alkynes are preferred in which the triple bond is bonded to an aromatic ring, very preferably n-prop-1-yn-1-yl, n-but-1-yn-1-yl, n-pent-1-yn-1-yl, and n-hex-1-yn-1-yl.
In case RF denotes a halogenated alkyl-, alkoxy-, alkenyl or alkenyloxy it can be branched or unbranched. Preferably it is unbranched, mono-poly or perfluorinated, preferably perfluorinated and has 1, 2, 3, 4, 5, 6 or 7 C atoms, in case of alkenyl 2, 3, 4, 5, 6 or 7 C atoms.
RP preferably denotes CN, NCS, Cl, F, —(CH2)n—CH═CF2, —(CH2)n—CH═CHF, —(CH2)n—CH═Cl2, —CnF2n+1, —(CF2)n—CF2H, —(CH2)n—CF3, —(CH2)n—CHF2, —(CH2)nCH2F, —CH═CF2, —O(CH2)n—CH═CF2, —O(CH2)nCHCl2, —OCnF2n+1, —O(CF2)n—CF2H, —O(CH2)nCF3, —O(CH2)n—CHF2, —O(CF)nCH2F, —OCF═CF2, —SCnF2n+1, —S(CF)n—CF3, wherein n is an integer from 0 to 7.
The compounds of the general formula AN are prepared by methods known per se, as described in the literature (for example in the standard works, such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), and under reaction conditions which are known and are suitable for said reactions. Use can be made here of variants which are commonly known but are not mentioned in detail here.
If desired, the starting materials can also be formed in situ by not isolating them from the reaction mixture, but instead by immediately reacting them further into the compounds of the general formula AN.
Preferred synthetic pathways towards compounds according to the invention are exemplified in the reaction schemes below in which the occurring groups and parameters have the meanings given for formula AN. The synthesis is further illustrated by means of the working examples and can be adapted to the particular desired compounds of the general formula AN by choice of suitable starting materials.
Preferred starting material for the synthesis of the compound of the formula AN are the compounds (1), scheme 1, in which suitable groups X are leaving groups selected from but not limited to Cl, Br, I, methanesulfonate (MsO), methylphenylsulfonate (TsO), trifluoromethanesulfonate (TfO), perfluorononylsulfonate (NsO), etc.
The compounds (1) can be reacted to terminal alkynes (2) by Sonogashira reaction with for example trimethylsilylacetylene followed by desilylation. The compounds (2) are transferred into the compounds of the formula AN by known methods such as for example deprotonation with butyllithium followed by reaction with p-toluenesulfonyl cyanide, 1-cyanoimidazole or 1-cyanobenzotriazole.
Other suitable starting materials for the synthesis of the compounds AN are the compounds (3) that are accessible from compounds (1) by Sonogashira reaction with prop-2-yn-1-ol.
The compounds (3) are transferred into the compounds of the formula AN oxidatively with diacetoxyiodobenzene according to J.-M. Vatele, Synlett (2014), 25 (9), 1275-1278.
In a preferred embodiment of the present invention, the compound of formula AN is selected from the compounds of the formulae AN-1, AN-2, AN-3, AN-4, and AN-5:
identically or differently, denote
in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms,
alternatively denotes
In the compounds of the formula AN and its sub-formulae, the groups V1 and V2, identically or differently, preferably denote —CR0═, in which R0 denotes H, Cl, F, CF3, CHF2, or CH3, very preferably F.
The compounds of the formula AN-1 are preferably selected from the compounds of the following formulae AN-1-1 to AN-4-8:
and where one or more non-adjacent CH2-groups may be replaced by O, and where in all of these groups one or more H atoms may be replaced by F.
Very preferred compounds of the formula AN are selected from the compounds of the formula AN-2-3, in particularly the compounds of the following sub-formulae:
According to another aspect of the invention there is provided a medium comprising one or more compounds of the formula AN.
In a preferred embodiment, the medium comprises one or more compounds selected from the group of compounds of the formulae ANa-I, ANa-II, ANa-III and ANa-IV:
identically or differently, denote
in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms,
alternatively denote
identically or differently, denote
in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms,
In a preferred embodiment the medium according to the invention comprises one or more compounds selected from the group of compounds of the formulae I, II and III:
preferably denotes
and the other preferably denotes
In the compounds of the formulae I, II and III, RL preferably denotes H. In another preferred embodiment, in the compounds of formulae I, II and III, one or two groups RL, preferably one group RL is different from H.
In a preferred embodiment of the present invention, the compounds of formula I are selected from the group of compounds of the formulae I-1 to I-5:
Preferably, the medium comprises one or more compounds selected from the compounds of the formula I-a and optionally one or more compounds selected from the compounds of the formula Cy-1
in which the occurring groups have the meanings given above for formula I-1. The total amount of compounds of the formula I-1 and/or Cy-I in the medium according to the invention is less than 10%, more preferably less than 5%, and in particular less than 2%. Particularly preferably, the medium contains no compound of formula Cy-1.
The media preferably comprise one or more compounds of formula I-1, which are preferably selected from the group of the compounds of the formulae I-1a to I-1d, preferably of formula I-1b:
in which R1 has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms or non-fluorinated alkynyl having 2 to 7 C atoms.
The media preferably comprise one or more compounds of formula I-2, which are preferably selected from the group of the compounds of the formulae I-2a to I-2e, preferably of formula I-2c:
in which R1 has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms or non-fluorinated alkynyl having 2 to 7 C atoms.
The media preferably comprise one or more compounds of formula I-3, which are preferably selected from the group of the compounds of the formulae I-3a to I-3d, particularly preferably of formula I-3b:
in which R1 has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms or non-fluorinated alkynyl having 2 to 7 C atoms.
The media preferably comprise one or more compounds of formula I-4, which are preferably selected from the group of the compounds of the formulae I-4a to I-4e, particularly preferably of formula I-4b:
in which R1 has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms or non-fluorinated alkynyl having 2 to 7 C atoms.
The media preferably comprise one or more compounds of formula I-5, which are preferably selected from the group of the compounds of the formulae I-5a to I-5d, particularly preferably of formula I-5b:
in which R1 has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms or non-fluorinated alkynyl having 2 to 7 C atoms.
The media preferably comprise one or more compounds of formula II, which are preferably selected from the group of the compounds of the formulae II-1 to II-3, preferably selected from the group of the compounds of the formulae II-1 and II-2:
in which the occurring groups have the meanings given under formula II above and preferably
The compounds of formula II-1 are preferably selected from the group of the compounds of the formulae II-1a to II-1e:
The compounds of formula II-2 are preferably selected from the group of the compounds of the formulae II-2a and II-2b:
The compounds of formula II-3 are preferably selected from the group of the compounds of the of formulae II-3a to II-3d:
The compounds of formula III are preferably selected from the group of the compounds of the formulae III-1 to III-6, more preferably of the formulae selected from the group of the compounds of the formulae III-1, III-2, III-3 and III-4, and particularly preferably of formula III-1:
The compounds of formula III-1 are preferably selected from the group of the compounds of the formulae III-1a to III-1j, more preferably selected from the group of the compounds of the formulae III-1a, III-1b, III-1g and III-1h, particularly preferably of formula III-1b and/or III-1h:
The compounds of formula III-2 are preferably compounds of formula III-2a to III-21, very preferably III-2b and/or III-2j:
The compounds of formula III-5 are preferably selected from the compounds of formula III-5a:
In a preferred embodiment, the media according to the invention comprise one or more compounds selected from the group of compounds of the formulae IIA-1-1 to IIA-1-12, very preferably IIA-1-1 or IIA-1-2:
Additionally, the liquid-crystalline media according to the present invention in a certain embodiment, which may be the same or different from the previous preferred embodiments preferably comprise one or more compounds of formula IV,
Very preferably, the compounds of formula IV are selected from the compounds of the formula IV-1
In a preferred embodiment of the present invention, the liquid-crystal medium additionally comprises one or more compounds selected from the group of compounds of the formulae V, VI, VII, VIII and IX:
In a preferred embodiment of the present invention, the liquid-crystal medium comprises one or more compounds of the formula V, preferably selected from the group of the compounds of the formulae V-1 to V-3, preferably of the formulae V-1 and/or V-2 and/or V-3, preferably of the formulae V-1 and V-2:
The compounds of the formula V-1 are preferably selected from the group of the compounds of the formulae V-1a to V-1d, preferably V-1c and V-1d:
The compounds of the formula V-2 are preferably selected from the group of the compounds of the formulae V-2a to V-2e and/or from the group of the compounds of the formulae V-2f and V-2g:
The compounds of the formula V-3 are preferably compounds of the formula V-3a:
The compounds of the formula V-1a are preferably selected from the group of the compounds of the formulae V-1a-1 and V-1a-2:
The compounds of the formula V-1b are preferably compounds of the formula V-1b-1:
The compounds of the formula V-1c are preferably selected from the group of the compounds of the formulae V-1c-1 to V-1c-4, particularly preferably selected from the group of the compounds of the formulae V-1c-1 and V-1c-2:
The compounds of the formula V-1d are preferably selected from the group of the compounds of the formulae V-1d-1 and V-1d-2, particularly preferably the compound of the formula V-1d-2:
The compounds of the formula V-2a are preferably selected from the group of the compounds of the formulae V-2a-1 and V-2a-2, particularly preferably the compounds of the formula V-2a-1:
Preferred combinations of R51 with R52, in particular in the case of formula V-2a-1, are (CnH2n+1 and CmH2m+1), (CnH2n+1 and O—CmH2m+1), (CH2═CH—(CH2)Z and CmH2m+1), (CH2═CH—(CH2)Z and O—CmH2m+1) and (CnH2n+1 and (CH2)Z—CH═CH2).
Preferred compounds of the formula V-2b are the compounds of the formula V-2b-1:
The preferred combination of R51 with R52 here is, in particular, CnH2n+1 and CmH2m+1. Preferred compounds of the formula V-2c are the compounds of the formula V-2c-1:
The preferred combination of (R51 and R52) here is, in particular, (CnH2n+1 and CmH2m+1).
Preferred compounds of the formula V-2d are the compounds of the formula V-2d-1:
The preferred combination of (R51 and R52) here is, in particular, (CnH2n+1 and CmH2m+1). Preferred compounds of the formula V-2e are the compounds of the formula V-2e-1:
The preferred combination of (R51 and R52) here is, in particular, (CnH2n+1 and O—CmH2m+1).
Preferred compounds of the formula V-2f are the compounds of the formula V-2f-1:
The preferred combinations of (R51 and R52) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). Preferred compounds of the formula V-2g are the compounds of the formula V-2g-1:
The preferred combinations of (R51 and R52) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and O—CmH2m+1).
The compounds of the formula VI are preferably selected from the group of the compounds of the formulae VI-1 to VI-5:
The compounds of the formula VI-1 are preferably selected from the group of the compounds of the formulae VI-1a and VI-1b, more preferably selected from compounds of the formula VI-1a:
The preferred combinations of (R61 and R62) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), in the case of formula VI-1a particularly preferably (CnH2n+1 and CmH2m+1) and in the case of formula VI-1b particularly preferably (CnH2n+1 and O—CmH2m+1).
The compounds of the formula VI-3 are preferably selected from the compounds of the formula VI-3a to VI-3e:
The compounds of the formula VI-4 are preferably selected from compounds of the formulae VI-4a to VI-4e:
The compounds of the formula VI-5 are preferably selected from the compounds of the formulae VI-5a to VI-5d, preferably VI-5b:
The compounds of the formula VII are preferably selected from the group of the compounds of the formulae VII-1 to VII-6:
The compounds of the formula VII-1 are preferably selected from the group of the compounds of the formulae VII-1a to VII-1d:
The compounds of the formula VII-2 are preferably selected from the group of the compounds of the formulae VII-2a and VII-2b, particularly preferably of the formula VII-2a:
The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1).
The compounds of the formula VII-3 are preferably compounds of the formula VII-3a:
The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1).
The compounds of the formula VII-4 are preferably compounds of the formula VII-4a:
The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1).
The compounds of the formula VII-5 are preferably selected from the group of the compounds of the formulae VII-5a and VII-5b, more preferably of the formula VII-5a:
The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1).
The compounds of the formula VII-6 are preferably selected from the group of the compounds of the formulae VII-6a and VII-6b:
The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1).
The compounds of the formula VII-7 are preferably selected from the group of the compounds of the formulae VII-7a to VII-7d:
The compounds of the formula VIII are preferably selected from the group of the compounds of the formulae VIII-1 to VIII-3, more preferably these compounds of the formula VIII predominantly consist, even more preferably essentially consist and very particularly preferably completely consist thereof:
The preferred combinations of (R81 and R82) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1).
The compounds of the formula VIII-1 are preferably selected from the group of the compounds of the formulae VIII-1a to VIII-1c:
The preferred combinations of (R81 and R82) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1).
The compounds of the formula VIII-2 are preferably compounds of the formula VIII-2a:
The preferred combinations of (R81 and R82) here are, in particular, (CnH2n+1 and CmH2m+1), (CnH2n+1 and O—CmH2m+1) and (CH2═CH—(CH2)z and CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1).
The compounds of the formula VIII-3 are preferably compounds of the formula VIII-3a:
The preferred combinations of (R81 and R82) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1).
The compounds of the formula IX are preferably selected from the group of the compounds of the formulae IX-1 to IX-3:
The preferred combinations of (R91 and R92) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1).
The compounds of the formula IX-1 are preferably selected from the group of the compounds of the formulae IX-1a to IX-1e:
The compounds of the formula IX-2 are preferably selected from the group of the compounds of the formulae IX-2a and IX-2b:
The preferred combination of (R91 and R92) here is, in particular, (CnH2n+1 and CmH2m+1).
The compounds of the formula IX-3 are preferably compounds of the formulae IX-3a and IX-3b:
The preferred combinations of (R91 and R92) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O—CmH2m+1), particularly preferably (CnH2n+1 and O—CmH2m+1).
In a preferred embodiment of the present invention the medium comprises one or more compounds of formula X
and
Preferably, the compounds of formula X are selected from the sub-formulae X-1 and X-2
Particularly preferably, the media according to the invention comprise one or more compounds selected from the group of compounds of the formulae X-1-1 to X-1-9
In which R101 denotes alkyl having 1 to 7 C atoms.
In a preferred embodiment, the medium according to the invention comprises one or more compounds of formula XIa and/or XIb
and where one or more non-adjacent CH2-groups may be replaced by O, and where in all of these groups one or more H atoms nay be replaced by F;
Preferably, the compounds of formula XI are selected from the group of compounds of the formulae XI-1 to XI-24:
Preferably, the medium comprises one or more compounds of formula XII
The compounds of formula XII are preferably selected from the compounds of the sub-formulae XII-1 to XII-11:
Very preferably, the medium comprises a compound of formula XII-3, in which the occurring groups have the meanings given above and particularly preferably L1 denotes H, X1, X2, X3 and X4 denote F and R12 denotes alkyl having 1 to 7 C atoms.
The medium according to the invention preferably comprises one or more compounds of the formula XIII
In a preferred embodiment of the present invention, the compounds of formula XIII are selected from the compounds of the formulae XIII-1 to XIII-20, very preferably from the compounds of the formulae XIII-1 to XIII-13:
in which the occurring groups have the meanings indicated above for formula XIII and its sub-formulae and preferably R13 denotes alkyl having 1 to 7 C atoms, Y1, Y2, Y3, and Y4, identically or differently, denote H, F, Cl, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl, and more preferably Y1 and Y2 independently denote H or F, in particular H, and Y3 and Y4 very preferably denote H, and L1 and L2, identically or differently, very preferably denote H, F, methyl or ethyl, in particular H.
Preferably the medium according to the invention comprises one or more compounds of the formula XIV
In a preferred embodiment of the present invention, the compound of formula XIV is selected from the compounds of the formulae XIV-1 and XIV-2:
In formula XIV and its sub-formulae,
preferably denote
in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or cycloalkyl having 3 to 5 C atoms,
In the formulae XIV-1 and XIV-2, preferably t2 and t4 are 0 or 1 where t2+t4 is 1 or 2. Preferred compounds of the formula XIV-1 are selected from the following sub-formulae:
have the meanings defined above and preferably
Very preferred are the compounds of the formulae XIV-1-1, XIV-1-2, XIV-1-3, XIV-1-4, XIV-1-9, XIV-1-10, XIV-1-11, XIV-1-12, XIV-2-1, XIV-2-2, XIV-2-3, XIV-2-4, XIV-2-9, XIV-2-10, XIV-2-11, and XIV-2-12.
Preferably, the medium according to the invention comprises one or more compounds of formula T
In a preferred embodiment, the liquid crystalline media according to the invention comprise one or more compounds selected from the group of compounds of the formulae T-1a to T-3b below:
In a particularly preferred embodiment of the present invention the media comprise one or more compounds selected from the compounds of the formulae T-1a and T-2a.
Preferred compounds of formula T-1a are selected from the group of compounds of the following sub-formulae:
Preferred compounds of formula T-2a are selected from the group of compounds of the following sub-formulae:
Preferred compounds of formula T-3a are selected from the group of compounds of the following sub-formulae:
Very preferably, the medium according to the invention comprises one or more compounds of formula T-1a-5.
In an embodiment, the medium according to the invention comprises one or more compounds of formula I, II, III, IV, V, VI, VII, VIII, IX, X in which the radical R1, R2, R3, R41, R42, R51, R52, R61, R62, R71, R72, R81, R82, R91, R92, R101, R102 and RS, respectively, is a cyclic alkyl group.
Very preferred compounds comprising a cyclic alkyl group are selected from the compounds of the formulae Cy-1 to Cy-14
In a preferred embodiment, the medium according to the invention comprises a compound of formula N
The compound of formula N is preferably selected from the group consisting of the formulae N-1, N-2 and N-3:
ZN1, ZN2, X1, X2 and n, have the respective meanings given above for formula N.
In formula N and its sub-formulae N-1, N-2 and N-3, preferably
on each occurrence, identically or differently denote
In a preferred embodiment, in formula N and its sub-formulae the radicals X1 and X2 both denote H.
In a preferred embodiment, in formula N and its sub-formulae the radical X1 denotes H and the radical X2 denotes F or Cl.
In a preferred embodiment, in formula N and its sub-formulae the radical X1 denotes F or Cl and the radical X2 denotes H.
In a preferred embodiment, in formula N and its sub-formulae the radicals X1 and X2 denote F or Cl, preferably both F.
The compounds of the formulae N-1, N-2 and N-3 are preferably selected from the group consisting of the formulae N-1-1 to N-1-10, N-2-1 to N-2-10 and N-3-1 to N-3-10:
in which RN, X1 and X2 have the meanings given above and L, on each occurrence identically or differently denotes H, F, methyl, ethyl or cyclopropyl.
In a preferred embodiment, the medium according to the invention comprises a compound of formula NI
ZN1, ZN2, W, X1, X2 and n, have the respective meanings given in claim 1 for formula N.
The compounds of formula NI are preferably selected from the compounds of the formulae NI-1 and NI-2
have the meanings given above for formula N, Y1 and Y2, identically or differently, denote H, F or Cl, and t is 0 or 1.
In the compounds of formula NI or NI-1 or NI-2,
independently of one another, preferably denote
In the compounds of formula NI or NI-1 or NI-2, ZN1 and ZN2, identically or differently, preferably denote —C≡C— or a single bond.
In a preferred embodiment of the present invention, the compounds of formula NI-1 and NI-2 are selected from the compounds of the formulae NI-1-1 to NI-1-12 and NI-2-1 to NI-2-12
In a preferred embodiment, in the compounds of formula NI and its sub-formulae, one or both of Y1 and Y2 denote H, preferably both.
In another preferred embodiment, in the compounds of formula N and its sub-formulae both of Y1 and Y2 denote F.
Preferably, the medium according to the invention comprises one or more compounds of formula UI
Preferably, the compounds of the formula UI are selected from the compounds of the formulae UI-1, UI-2, UI-3, UI-4 and UI-5:
Very preferred compounds of formula UI are selected from the following sub-formulae:
The medium according to the invention preferably comprises one or more compounds of the formulae GF-1-1 to GF-5-1:
The media according to the present invention comprise one or more chiral dopants. Preferably these chiral dopants have an absolute value of the helical twisting power (HTP) in the range of from 1 μm−1 to 150 μm−1, preferably in the range of from 10 μm−1 to 100 μm−1. In case the media comprise two or more chiral dopants, these may have opposite signs of their HTP-values. This condition is preferred for some specific embodiments, as it allows to compensate the chirality of the respective compounds to some degree and, thus, may be used to compensate various temperature dependent properties of the resulting media in the devices. Generally, however, it is preferred that most, preferably all of the chiral compounds present in the media according to the present invention have the same sign of their HTP-values.
Preferably the chiral dopants present in the media according to the instant application are mesogenic compounds and most preferably they exhibit a mesophase on their own.
In a preferred embodiment of the present invention, the medium comprises two or more chiral compounds which all have the same algebraic sign of the HTP.
The temperature dependence of the HTP of the individual compounds may be high or low. The temperature dependence of the pitch of the medium can be compensated by mixing compounds having different temperature dependencies of the HTP in corresponding ratios.
For the optically active component, a multitude of chiral dopants, some of which are commercially available, is available to the person skilled in the art, such as, for example, cholesteryl nonanoate, R— and S-811, R— and S-1011, R— and S-2011, R— and S-3011, R— and S-4011, or CB15 (all Merck KGaA, Darmstadt).
Particularly suitable dopants are compounds which contain one or more chiral groups and one or more mesogenic groups, or one or more aromatic or alicyclic groups which form a mesogenic group with the chiral group.
Suitable chiral groups are, for example, chiral branched hydrocarbon radicals, chiral ethane diols, binaphthols or dioxolanes, furthermore mono- or polyvalent chiral groups selected from the group consisting of sugar derivatives, sugar alcohols, sugar acids, lactic acids, chiral substituted glycols, steroid derivatives, terpene derivatives, amino acids or sequences of a few, preferably 1-5, amino acids.
Preferred chiral groups are sugar derivatives, such as glucose, mannose, galactose, fructose, arabinose and dextrose; sugar alcohols, such as, for example, sorbitol, mannitol, iditol, galactitol or anhydro derivatives thereof, in particular dianhydrohexitols, such as dianhydrosorbide (1,4:3,6-dianhydro-D-sorbide, isosorbide), dianhydromannitol (isosorbitol) or dianhydroiditol (isoiditol); sugar acids, such as, for example, gluconic acid, gulonic acid and ketogulonic acid; chiral substituted glycol radicals, such as, for example, mono- or oligoethylene or propylene glycols, in which one or more CH2 groups are substituted by alkyl or alkoxy; amino acids, such as, for example, alanine, valine, phenylglycine or phenylalanine, or sequences of from 1 to 5 of these amino acids; steroid derivatives, such as, for example, cholesteryl or cholic acid radicals; terpene derivatives, such as, for example, menthyl, neomenthyl, campheyl, pineyl, terpineyl, isolongifolyl, fenchyl, carreyl, myrthenyl, nopyl, geraniyl, linaloyl, neryl, citronellyl or dihydrocitronellyl.
The media according to the present invention preferably comprise chiral dopants which are selected from the group of known chiral dopants. Suitable chiral radicals and mesogenic chiral compounds are described, for example, in DE 35 23 185 (internal priority DE 34 25 503), DE 35 34 777, DE 35 34 778, DE 36 17 826 (internal priority DE 35 34 779) and DE 35 34 780, DE 43 42 280, EP 01 038 941 and DE 195 41 820. Examples are also compounds listed in Table F below.
Chiral compounds preferably used according to the present invention are selected from the group consisting of the formulae shown below.
Particular preference is given to chiral dopants selected from the group consisting of compounds of the following formulae A-I to A-III and A-Ch:
Particular preference is given to dopants selected from the group consisting of the compounds of the following formulae:
Particularly preferred compounds of formula A are compounds of formula A-III.
Further preferred dopants are derivatives of the isosorbide, isomannitol or isoiditol of the following formula A-IV:
is
(dianhydrosorbitol),
(dianhydromannitol), or
(dianhydroiditol),
preferably dianhydrosorbitol,
and chiral ethane diols, such as, for example, diphenylethanediol (hydrobenzoin), in particular mesogenic hydrobenzoin derivatives of the following formula A-V:
including the (S,S) enantiomers, which are not shown,
in which
Examples of compounds of formula A-IV are:
The compounds of the formula A-IV are described in WO 98/00428. The compounds of the formula A-V are described in GB-A-2,328,207.
Very particularly preferred dopants are chiral binaphthyl derivatives, as described in WO 02/94805, chiral binaphthol acetal derivatives, as described in WO 02/34739, chiral TADDOL derivatives, as described in WO 02/06265, and chiral dopants having at least one fluorinated bridging group and a terminal or central chiral group, as described in WO 02/06196 and WO 02/06195.
Particular preference is given to chiral compounds of the formula A-VI
is
or
is
both are a single bond,
Particular preference is given to chiral binaphthyl derivatives of the formula A-VI-1
The concentration of the one or more chiral dopant(s), in the LC medium is preferably in the range from 0.001% to 20%, preferably from 0.05% to 5%, more preferably from 0.1% to 2%, and, most preferably from 0.5% to 1.5%. These preferred concentration ranges apply in particular to the chiral dopant S-4011 or R-4011 (both from Merck KGaA) and for chiral dopants having the same or a similar HTP. For Chiral dopants having either a higher or a lower absolute value of the HTP compared to S-4011 these preferred concentrations have to be decreased, respectively increased proportionally according to the ratio of their HTP values relatively to that of S-4011.
The pitch p of the LC media or host mixtures according to the invention is preferably in the range of from 5 to 50 μm, more preferably from 8 to 30 μm and particularly preferably from 10 to 20 μm.
Preferably, the media according to the invention comprise a stabilizer selected from the group of compounds of the formulae ST-1 to ST-22.
Of the compounds of the formula ST, special preference is given to the compounds of the formulae
In the compounds of the formulae ST-3a and ST-3b, n preferably denotes 3. In the compounds of the formula ST-2a, n preferably denotes 7.
Very particularly preferred mixtures according to the invention comprise one or more stabilisers from the group of the compounds of the formulae ST-2a-1, ST-3a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12:
The compounds of the formulae ST-1 to ST-12 are preferably each present in the liquid-crystal mixtures according to the invention in amounts of 0.005-0.5%, based on the mixture, very preferably in an amount of 100 ppm, 250 ppm, 500 ppm or 1000 ppm.
If the mixtures according to the invention comprise two or more compounds from the group of the compounds of the formulae ST-1 to ST-18, the concentration correspondingly increases to 0.01-1% in the case of two compounds, based on the mixtures.
However, the total proportion of the compounds of the formulae ST-1 to ST-18, based on the mixture according to the invention, should not exceed 2%.
Other mesogenic compounds which are not explicitly mentioned above can optionally and advantageously also be used in the media in accordance with the present invention. Such compounds are known to the person skilled in the art.
In a preferred embodiment of the present invention the medium comprises one or more compounds of formula AN in a total concentration of 1% to 20%, more preferably 5% to 16%, particularly preferably 8% to 14%.
In another preferred embodiment of the present invention the medium comprises one or more compounds of formula AN in a total concentration of 20% to 50%, more preferably 25% to 45%, particularly preferably 28% to 40%.
In another preferred embodiment, the medium comprises one or more compounds of formula I, preferably of formula I-2 or 1-3, in a total concentration in the range of from 1% to 30%, more preferably from 2% to 25%, very preferably 3% to 20% and particularly preferably from 5% to 15%.
In another preferred embodiment, the medium comprises one or more compounds of formula I, preferably of formula I-2 or 1-3, in a total concentration in the range of from 20% to 80%, more preferably from 35% to 75%, very preferably 45% to 70% and particularly preferably from 52% to 60%.
In a preferred embodiment of the present invention the medium comprises one or more compounds of formula II, preferably of formula II-1, in a total concentration of 2% to 35%, more preferably 3% to 30%, particularly preferably 5% to 25%.
In another preferred embodiment of the present invention the medium comprises one or more compounds of formula II, preferably of formula II-1, in a total concentration of 4% to 30%, more preferably 7% to 25%, particularly preferably 10% to 20%.
In a preferred embodiment of the present invention the medium comprises one or more compounds of formula IIA-1 in a total concentration of 5% to 25%, more preferably 8% to 20%, particularly preferably 12% to 17%.
In a preferred embodiment of the present invention the medium comprises one or more compounds of formula II-1 in a total concentration of 30% or less, more preferably 25% or less, particularly preferably 22% or less.
In a preferred embodiment of the present invention the medium comprises one or more compounds of formula III, preferably III-1 and/or III-2, more preferably III-1f and/or III-1b, and/or III-1h in a total concentration of 5% to 40%, more preferably 10% to 30%, particularly preferably 15% to 25%.
In another preferred embodiment of the present invention the medium comprises one or more compounds of formula III, preferably III-1 and/or III-2, more preferably III-1f and/or III-1b, and/or III-1h in a total concentration of 15% to 60% or 65% or 70%, more preferably 20% to 58%, particularly preferably 30% to 55% or 35% to 53%.
In a preferred embodiment of the present invention, the liquid-crystalline media comprise a compound of formula T, preferably in a total concentration in the range of from 5% to 35%, more preferably 6% to 30% and particularly preferably 7% to 25%, preferably selected from the formulae T-1a, T-2a and T-3a, very preferably selected from T-1a-5, T-2a-2, T-2a-4 and T-3a-2.
In a preferred embodiment of the present invention the medium comprises one or more compounds of formula XII, preferably in a total concentration of 5% to 30%, more preferably 8% to 25%, particularly preferably 10% to 20%.
In a preferred embodiment, the medium comprises one or more compounds of the formula AN and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII, T, preferably in a total concentration of 90% or more, more preferably 95%, 96% or 97% or more, very preferably 98% or more and in particular 99% or more.
In a preferred embodiment, the medium comprises one or more compounds of the formula AN and one or more compounds selected from the group consisting of the formulae ANa, I, II and/or IIA, III, XII, T in a total concentration in the range of from 40% to 90% and a total concentration of 10% or more of one or more compounds of the formula IV.
In a preferred embodiment, the medium comprises one or more compounds of the formula AN and one or more compounds selected from the group consisting of the formulae ANa, I, II and/or IIA, III, XII and T in a total concentration in the range of from 40% to 70% and a total concentration of 30% or more of one or more compounds of the formula IV.
In a preferred embodiment, the medium comprises one or more compounds of the formula AN and one or more compounds selected from the group consisting of the formulae ANa, I, II and/or IIA, III, XII and T in a total concentration in the range of from 40% to 60% and a total concentration of 40% or more of one or more compounds of the formula IV.
In a preferred embodiment, the medium comprises 90%, 95%, 96%, 97%, 98% or more of compounds selected from the formulae AN and ANa.
In a preferred embodiment, the medium comprises 5% to 40%, more preferably 10% to 30%, very preferably 15% to 25% of one or more compounds of the formula IV.
In a preferred embodiment, the medium comprises 30% to 70%, preferably 40% to 60% of one or more compounds selected from the group of compounds of the formulae AN and ANa and 70% to 30%, preferably 60% to 40% of one or more compounds selected from the group of compounds of the formulae I, II, III, XII and T.
Further preferred embodiments of the present invention, taken alone or in combination with one another, are as follows, wherein some compounds are abbreviated using the acronyms as described in Tables A and B and given in Table C below and n is 1, 2, 3, 4, 5, 6, or 7:
The liquid-crystal media in accordance with the present invention preferably have a clearing point of 90° C. or more, more preferably 100° C. or more, more preferably 110° C. or more, more preferably 120° C. or more, more preferably 130° C. or more, particularly preferably 140° C. or more and very particularly preferably 150° C. or more.
The nematic phase of the media according to the invention preferably extends at least from 0° C. or less to 90° C. or more. It is advantageous for the media according to the invention to exhibit even broader nematic phase ranges, preferably at least from −10° C. or less to 120° C. or more, very preferably at least from −20° C. or less to 140° C. or more and in particular at least from −30° C. or less to 150° C. or more, very particularly preferably at least from −40° C. or less to 170° C. or more.
The Δε of the liquid-crystal medium according to the present invention, at 1 KHz and 20° C., is preferably 5 or more, more preferably 7 or more and very preferably 8 or more.
The birefringence (Δn) of the liquid-crystal media according to the present invention, at 589 nm (NaD) and 20° C., is preferably 0.280 or more, more preferably 0.300 or more, even more preferably 0.320 or more, very preferably 0.330 or more and in particular 0.350 or more.
In a preferred embodiment of the present application, the Δn of the liquid-crystal media in accordance with the present invention is preferably 0.50 or more, more preferably 0.55 or more.
The compounds of the formulae I to III in each case include dielectrically positive compounds having a dielectric anisotropy of greater than 3, dielectrically neutral compounds having a dielectric anisotropy of less than 3 and greater than −1.5 and dielectrically negative compounds having a dielectric anisotropy of −1.5 or less.
The compounds of the formulae AN, I, II and III are preferably dielectrically positive.
Preferably, the optical component according to the invention is designed and configured as an optical phase modulator.
In a preferred embodiment, the optical component according to the invention is designed and configured for use in a transparent device for phase modulation of IR radiation.
In another preferred embodiment, the optical component according to the invention is designed and configured for use in a reflective device for phase modulation of IR radiation.
A typical electro-optical modulator comprises conducting, infrared transmitting windows consisting for example of Ge, separated from one another by spacers and having a cell gap in the range of from 1 mm to 5 mm.
According to another aspect of the present invention there is provided a LIDAR scanning system as described in WO2018/156643 A1, including a laser configured to emit pulses of light at an operating wavelength in the infrared. The LIDAR scanning system includes a transmit reconfigurable-metasurface configured to reflect an incident pulse of light from the laser as an illumination beam pointing at a selected portion of a field of view, preferably a two-dimensional field of view. The pointing of the illumination beam is responsive to a first selected holographic beam steering pattern implemented in the transmit reconfigurable-metasurface. The system further includes a receive reconfigurable-metasurface configured to reflect a return of the illumination beam from the selected portion of the field of view as a relay beam pointing at an optical detector. The pointing of the relay beam is responsive to a second selected holographic beam steering pattern implemented in the receiving reconfigurable metasurface. The system includes an optical detector comprising an array of detector pixels. Each detector pixel includes (i) a photodetector configured to detect light in the return of the illumination beam and (ii) a timing circuit configured to determine a time of flight of the detected light. The optical detector is also configured to output a detection signal indicative of the detected light and a time of flight of the detected light for each pixel of the array. The transmit reconfigurable-metasurface includes a plurality of dynamically adjustable high-Q dielectric resonators arranged on a surface of the reconfigurable-metasurface with inter-element spacing less than the operating wavelength of the laser, where the surface of the reconfigurable-metasurface includes a conducting surface, and the plurality of resonators have a corresponding plurality of adjustable reflection phases providing a dynamically adjustable reflected wave responsive to an incident wave, wherein the conducting surface and the plurality of resonators define a metasurface. Each of the plurality of dielectric resonators includes (i) a pair of regions having high refractive index; and (ii) an electrically adjustable material disposed in a gap between the regions, wherein the electrically adjustable material is a liquid crystal material as set forth above and below.
According to another aspect of the invention there is provided a reflective spatial light modulator, in particular an LCoS device including the liquid crystal material according to the invention, sandwiched between a transparent glass layer having a transparent electrode, a mirror mounted on a silicon CMOS backplane and PCB. The mirror is divided into a two-dimensional array of individually addressable pixels. Each pixel is individually drivable by a voltage signal to provide a local phase change to at least one polarization component of an optical signal, thereby providing a two-dimensional array of phase manipulating regions. Pre-alignment of the liquid crystal is provided by alignment layers.
Said LCoS device is useful for the integration into optical devices. Preferred devices are a wavelength selective switch (WSS), LIDAR scanner, infrared scene projector, as well as other beam steering applications as shown in the article Micallef, F. (2019). Middle infrared beam-steering using liquid crystals for spatial light modulation (Doctoral thesis). https://doi.org/10.17863/CAM.39602 (https://www.repository.cam.ac.uk/handle/1810/292443).
In the present application, the expression dielectrically positive describes compounds or components where Δε>3.0, dielectrically neutral describes those where −1.5≤Δε≤3.0 and dielectrically negative describes those where Δε<−1.5. Δε is determined at a frequency of 1 kHz and at 20° C. The dielectric anisotropy of the respective compound is determined from the results of a solution of 10% of the respective individual compound in a nematic host mixture. If the solubility of the respective compound in the host mixture is less than 10%, the concentration is reduced to 5%. The capacitances of the test mixtures are determined both in a cell having homeotropic alignment and in a cell having homogeneous alignment. The cell thickness of both types of cells is approximately 20 μm. The voltage applied is a rectangular wave having a frequency of 1 kHz and an effective value of typically 0.5 V to 1.0 V, but it is always selected to be below the capacitive threshold of the respective test mixture.
The host mixture used for the determination of physical constants of pure compounds by extrapolation is ZLI-4792 from Merck KGaA, Germany. The absolute values of the dielectric constants, the birefringence (Δn) and the rotational viscosity (γ1) of the compounds are determined from the change in the respective values of the host mixture on addition of the compounds. The concentration in the host is 10% or in case of insufficient solubility 5%. The values are extrapolated to a concentration of 100% of the added compounds.
In the examples, the phase sequences of pure compounds are given using the following abbreviations:
Components having a nematic phase at the measurement temperature of 20° C. are measured as such, all others are treated like compounds.
The expression threshold voltage in the present application refers to the optical threshold and is quoted for 10% relative contrast (V10), and the expression saturation voltage refers to the optical saturation and is quoted for 90% relative contrast (V90), in both cases unless expressly stated otherwise. The capacitive threshold voltage (V0), also called the Freedericks threshold (VFr), is only used if expressly mentioned.
The parameter ranges indicated in this application all include the limit values, unless expressly stated otherwise.
The different upper and lower limit values indicated for various ranges of properties in combination with one another give rise to additional preferred ranges.
Throughout this application, the following conditions and definitions apply, unless expressly stated otherwise. All concentrations are quoted in percent by weight and relate to the respective mixture as a whole, all temperatures are quoted in degrees Celsius and all temperature differences are quoted in differential degrees. All physical properties are determined in accordance with “Merck Liquid Crystals, Physical Properties of Liquid Crystals”, Status November 1997, Merck KGAA, Germany, and are quoted for a temperature of 20° C., unless expressly stated otherwise. The optical aniso-tropy (Δn) is determined at a wavelength of 589.3 nm. The dielectric anisotropy (Δε) is determined at a frequency of 1 kHz. The threshold voltages, as well as all other electro-optical properties, are determined using test cells produced at Merck KGaA, Germany. The test cells for the determination of Δε have a cell thickness of approximately 20 μm. The electrode is a circular ITO electrode having an area of 1.13 cm2 and a guard ring. The orientation layers are SE-1211 from Nissan Chemicals, Japan, for homeotropic orientation (ε∥) and polyimide AL-1054 from Japan Synthetic Rubber, Japan, for homogeneous orientation (ε⊥). The capacitances are determined using a Solatron 1260 frequency response analyser using a sine wave with a voltage of 0.3 Vrms. The light used in the electro-optical measurements is white light. A set-up using a commercially available DMS instrument from Autronic-Melchers, Germany, is used here. The characteristic voltages have been determined under perpendicular observation. The threshold (V10), mid-grey (V50) and saturation (V90) voltages have been determined for 10%, 50% and 90% relative contrast, respectively.
The liquid-crystalline media are investigated with respect to their properties in the microwave frequency range as described in A. Penirschke et al. “Cavity Perturbation Method for Characterization of Liquid Crystals up to 35 GHZ”, 34th European Microwave Conference—Amsterdam, pp. 545-548. Compare in this respect also A. Gaebler et al. “Direct Simulation of Material Permittivities . . . ”, 12MTC 2009-International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), pp. 463-467, and DE 10 2004 029 429 A, in which a measurement method is likewise described in detail.
The liquid crystal is introduced into a polytetrafluoroethylene (PTFE) or quartz capillary. The capillary has an inner diameter of 0.5 mm and an outer diameter of 0.78 mm. The effective length is 2.0 cm. The filled capillary is introduced into the centre of the cylindrical cavity with a resonance frequency of 19 GHz. This cavity has a length of 11.5 mm and a radius of 6 mm. The input signal (source) is then applied, and the frequency-depending response of the cavity is recorded using a commercial vector network analyser (N5227A PNA Microwave Network Analyzer, Keysight Technologies Inc. USA. For other frequencies, the dimensions of the cavity are adapted correspondingly.
The change in the resonance frequency and the Q factor between the measurement with the capillary filled with the liquid crystal and the measurement without the capillary filled with the liquid crystal is used to determine the dielectric constant and the loss angle at the corresponding target frequency by means of equations 10 and 11 in the above-mentioned publication A. Penirschke et al., 34th European Microwave Conference—Amsterdam, pp. 545-548, as described therein.
The values for the components of the properties perpendicular and parallel to the director of the liquid crystal are obtained by alignment of the liquid crystal in a magnetic field. To this end, the magnetic field of a permanent magnet is used. The strength of the magnetic field is 0.35 tesla.
Preferred components are phase shifters, varactors, wireless and radio wave antenna arrays, matching circuit adaptive filters and others.
In the present application, the term compounds is taken to mean both one compound and a plurality of compounds, unless expressly stated otherwise.
All mixtures according to the invention are nematic. The liquid-crystal media according to the invention preferably have nematic phases in preferred ranges given above. The expression have a nematic phase here means on the one hand that no smectic phase and no crystallisation are observed at low temperatures at the corresponding temperature and on the other hand that no clearing occurs on heating from the nematic phase. At high temperatures, the clearing point is measured in capillaries by conventional methods. The investigation at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storage of bulk samples: The storage stability in the bulk (LTS) of the media according to the invention at a given temperature T is determined by visual inspection. 2 g of the media of interest are filled into a closed glass vessel (bottle) of appropriate size placed in a refrigerator at a predetermined temperature. The bottles are checked at defined time intervals for the occurrence of smectic phases or crystallisation. For every material and at each temperature two bottles are stored. If crystallisation or the appearance of a smectic phase is observed in at least one of the two correspondent bottles the test is terminated and the time of the last inspection before the one at which the occurrence of a higher ordered phase is observed is recorded as the respective storage stability. The test is finally terminated after 1000 h, i.e. an LTS value of 1000 h means that the mixture is stable at the given temperature for at least 1000 h.
The liquid crystals employed preferably have a positive dielectric anisotropy. This is preferably 2 or more, preferably 4 or more, particularly preferably 6 or more and very particularly preferably 10 or more.
Furthermore, the liquid-crystal media according to the invention are characterised by high anisotropy values in the microwave range. The birefringence at about 19 GHz is, for example, preferably 0.14 or more, particularly preferably 0.15 or more, particularly preferably 0.20 or more, particularly preferably 0.25 or more and very particularly preferably 0.30 or more. In addition, the birefringence is preferably 0.80 or less.
The dielectric anisotropy in the microwave range is defined as
The tunability (τ) is defined as
The material quality (figure of merit) η is defined as
where
the maximum dielectric loss is
The tunability τ of the medium according to the invention, measured at 20° C. and 19 GHz is 0.250 or more, preferably 0.300 or more, 0.310 or more, 0.320 or more, 0.330 or more, or 0.340 or more, very preferably 0.345 or more and in particular 0.350 or more.
The material quality (η) of the preferred liquid-crystal materials is 6 or more, preferably 8 or more, preferably 10 or more, preferably 15 or more, preferably 17 or more, preferably 20 or more, particularly preferably 25 or more and very particularly preferably 30 or more.
In the corresponding components, the preferred liquid-crystal materials have phase shifter qualities of 15°/dB or more, preferably 20°/dB or more, preferably 30°/dB or more, preferably 40°/dB or more, preferably 50°/dB or more, particularly preferably 80°/dB or more and very particularly preferably 100°/dB or more.
In some embodiments, however, liquid crystals having a negative value of the dielectric anisotropy can also advantageously be used.
The liquid crystals employed are either individual substances or mixtures. They preferably have a nematic phase.
The liquid-crystal media in accordance with the present invention may comprise further additives and chiral dopants in the usual concentrations. The total concentration of these further constituents is in the range from 0% to 10%, preferably 0.1% to 6%, based on the mixture as a whole. The concentrations of the individual compounds used are each preferably in the range from 0.1% to 3%. The concentration of these and similar additives is not taken into consideration when quoting the values and concentration ranges of the liquid-crystal components and liquid-crystal compounds of the liquid-crystal media in this application.
Preferably the media according to the present invention comprise one or more chiral compounds as chiral dopants in order to adjust their cholesteric pitch. Their total concentration in the media according to the instant invention is preferably in the range 0.05% to 15%, more preferably from 1% to 10% and most preferably from 2% to 6%.
Optionally the media according to the present invention may comprise further liquid crystal compounds in order to adjust the physical properties. Such compounds are known to the skilled person. Their concentration in the media according to the instant invention is preferably 0% to 30%, more preferably 0.1% to 20% and most preferably 1% to 15%.
The response times are given as rise time (τon) for the time for the change of the relative tuning, respectively of the relative contrast for the electro-optical response, from 0% to 90% (t90−t0), i.e. including the delay time (t10−t0), as decay time (τoff) for the time for the change of the relative tuning, respectively of the relative contrast for the electro-optical response, from 100% back to 10% (t100−t10) and as the total response time (τtotal=τon+τoff), respectively.
The liquid-crystal media according to the invention consist of a plurality of compounds, preferably 3 to 30, more preferably 4 to 20 and very preferably 4 to 16 compounds. These compounds are mixed in a conventional manner. In general, the desired amount of the compound used in the smaller amount is dissolved in the compound used in the larger amount. If the temperature is above the clearing point of the compound used in the higher concentration, it is particularly easy to observe completion of the dissolution process. It is, however, also possible to prepare the media in other conventional ways, for example using so-called pre-mixes, which can be, for example, homologous or eutectic mixtures of compounds, or using so-called “multibottle” systems, the constituents of which are themselves ready-to-use mixtures.
All temperatures, such as, for example, the melting point T(C,N) or T(C,S), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I) of the liquid crystals, are quoted in degrees Celsius. All temperature differences are quoted in differential degrees.
In the present invention and especially in the following examples, the structures of the mesogenic compounds are indicated by means of abbreviations, also referred to as acronyms. In these acronyms, the chemical formulae are abbreviated as follows using Tables A to C below. All groups CnH2n+1, CmH2m+1 and ClH2l+1, and CnH2n−1, CmH2m−1 and ClH2l−1 denote straight-chain alkyl or alkylene, respectively, in each case having n, m or I C atoms, wherein n and m, independently are 1, 2, 3, 4, 5, 6 or 7 and I is 1, 2 or 3. Table A lists the codes used for the ring elements of the core structures of the compounds, while Table B shows the linking groups and end groups. Table C shows illustrative structures of compounds with their respective abbreviations.
in which n and m each denote integers, and the three dots “ . . . ” are placeholders for other abbreviations from this table.
Branched lateral groups are numbered starting from the position next to the ring (1) where the longest chain is selected, the smaller number indicating the length of the branch and the superscript number in brackets indicates the position of the branch, for example:
The following table shows illustrative structures together with their respective abbreviations. These are shown in order to illustrate the meaning of the rules for the abbreviations. They furthermore represent compounds which are preferably used.
The following illustrative structures are examples as well as compounds, which are preferably additionally used in the media:
Preferably, the medium according to the invention comprises one or more compounds selected from the compounds of Table C.
The following table, Table D, shows illustrative compounds which can be used as alternative stabilisers in the mesogenic media in accordance with the present invention. The total concentration of these and similar compounds in the media is preferably 5% or less.
In a preferred embodiment of the present invention, the mesogenic media comprise one or more compounds selected from the group of the compounds from Table D. The following table, Table E, shows illustrative compounds which can preferably be used as chiral dopants in the mesogenic media in accordance with the present invention.
In a preferred embodiment of the present invention, the mesogenic media comprise one or more compounds selected from the group of the compounds of Table E. The mesogenic media in accordance with the present application preferably comprise two or more, preferably four or more, compounds selected from the group consisting of the compounds from the above tables.
Unless indicated otherwise, parts or percent data denote parts by weight or percent by weight.
Above and below:
Unless explicitly noted otherwise, all values indicated in the present application for temperatures, such as, for example, the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I) or cl. p., are indicated in degrees Celsius (° C.). M.p. denotes melting point. Furthermore, Tg=glass state, C=crystalline state, N=nematic phase, S=smectic phase and I=isotropic phase. The numbers between these symbols represent the transition temperatures.
The term “threshold voltage” for the present invention relates to the capacitive threshold (V0), also called the Freedericksz threshold, unless explicitly indicated otherwise. In the examples, as is generally usual, the optical threshold can also be indicated for 10% relative contrast (V10).
The display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates at a separation of 20 μm, which each have on the insides an electrode layer and an unrubbed polyimide alignment layer on top, which cause a homeotropic edge alignment of the liquid-crystal molecules.
The so-called “HTP” denotes the helical twisting power of an optically active or chiral substance in an LC medium (in μm). Unless indicated otherwise, the HTP is measured in the commercially available nematic LC host mixture MLD-6260 (Merck KGaA) at a temperature of 20° C.
The Clearing point is measured using the Mettler Thermosystem FP900. The optical anisotropy (Δn) is measured using an Abbe Refractometer H005 (Natrium-spectral lamp Na10 at 589 nm, 20° C.). The dielectric anisotropy (Δε) is measured using an LCR-Meter E4980A/Agilent (G005) at 20° C. (ε-parallel-cells with JALS 2096-R1). The turn on voltage (V0) is measured using an LCR-Meter E4980A/Agilent (G005) at 20° C. (ε-parallel-cells with JALS 2096-R1). The rotational viscosity (γ1) is measured using a TOYO LCM-2 (0002) at 20° C. (gamma 1 negative cells with JALS-2096-R 1). The elastic constant (K1, splay) is measured using an LCR-Meter E4980A/Agilent (G005) at 20° C. (ε parallel-cells with JALS 2096-R1). K3: The elastic constant (K3, bend) is measured using an LCR-Meter E4980A/Agilent (G005) at 20° C. (ε-parallel-cells with JALS 2096-R1).
Unless explicitly noted otherwise, all concentrations in the present application are indicated in percent by weight and relate to the corresponding mixture as a whole, comprising all solid or liquid-crystalline components, without solvents. All physical properties are determined in accordance with “Merck Liquid Crystals, Physical Properties of Liquid Crystals”, Status November 1997, Merck KGaA, Germany, and apply for a temperature of 20° C., unless explicitly indicated otherwise.
The present invention is illustrated in detail by the following non-restrictive working examples.
A solution of 5-bromo-1,3-difluoro-2-iodobenzene (CAS 160976-02-3) (11.0 g, 35 mmol) in triethylamine (25 ml) and THF (50 ml) is treated with bis(triphenylphosphine)palladium(II) chloride (448 mg, 0.6 mmol) and copper(I) iodide (122 mg, 0.6 mmol) under Argon atmosphere at room temp., followed by addition of a solution of 1-ethynyl-4-pentylbenzene (CAS 79887-10-8) (5.5 g, 32 mmol) in THF (10 ml). The reaction mixture is stirred for 24 h at room temp. It is quenched with dist. water and MTB ether, the aqueous phase is separated and extracted with MTB ether, and the combined organic phases are washed with brine, dried (sodium sulfate) and concentrated i. vac. The residue is purified by flash chromatography (silica gel, eluent heptane) and crystallization (heptane) to give colorless crystals of 5-bromo-1,3-difluoro-2-((4-pentylphenyl)ethynyl)benzene.
A solution of 5-bromo-1,3-difluoro-2-((4-pentylphenyl)ethynyl)benzene (9.7 g, 27 mmol) in triethylamine (70 ml) is treated with bis(triphenylphosphine)palladium(II) chloride (700 mg, 1.0 mmol) and copper(I) iodide (50 mg, 0.3 mmol) under Argon atmosphere at room temp., followed by addition of trimethylsilyl acetylene (7.7 ml, 55 mmol) at 50° C. The reaction mixture is stirred for 4 h under reflux, is cooled to room temp. and filtered through Celite. The residue is washed with brine, dried (sodium sulfate) and concentrated i. vac. The crude product is purified by flash chromatography (silica gel, eluent heptane) to give ((3,5-difluoro-4-((4-pentylphenyl)ethynyl)phenyl)ethynyl)trimethylsilane as a yellow oil.
Tetrabutylammonium fluoride (25 ml of a 1 M solution in THF) is added dropwise to a solution of ((3,5-difluoro-4-((4-pentylphenyl)ethynyl)phenyl)ethynyl)trimethylsilane (9.3 g, 24 mmol) in THF (100 ml) at 15° C. The reaction mixture is stirred at room temp. overnight. It is then quenched with dist. water and MTB ether and acidified with hydrochloric acid (1 M). The aqueous phase is separated and extracted with MTB ether, and the combined organic phases are washed with brine, dried (sodium sulfate) and concentrated i. vac. The crude product is purified by flash chromatography (silica gel, eluent heptane) to give 5-ethynyl-1,3-difluoro-2-((4-pentylphenyl)ethynyl)benzene as a colorless solid.
n-Butyllithium (8.0 ml, 15% solution in n-hexane) is added to a solution of 5-ethynyl-1,3-difluoro-2-((4-pentylphenyl)ethynyl)benzene (3.5 g, 11 mmol) in THF (40 ml) at −70° C. under Argon atmosphere, and the mixture is stirred at −70° C. for 2 h. Then a suspension of p-toluene sulfonyl cyanide (2.3 g, 13 mmol) in THF (10 ml) is added at −70° C., and the reaction mixture is stirred for 1 h at −70° C. and 3 h at room temp. It is quenched with dist. water, acidified with hydrochloric acid (1 M), and diluted with ethyl acetate. The aqueous phase is separated and extracted with ethyl acetate, and the combined organic phases are dried (sodium sulfate) and concentrated i. vac. The crude product is purified by flash chromatography (silica gel, eluent heptane/1-chlorobutane) and crystallization (heptane) to give pale yellow crystals of 3-{4-[2-(4-pentylphenyl)ethynyl]-3,5-difluorophenyl}prop-2-ynenitrile.
Phase sequence: K 94 N 146 I
Phase sequence K 108 N 143 I.
A solution of 4-bromo-2-ethyl-2-iodobenzene (CAS 175278-30-5) (232.4 g, 0.75 mol) in triethylamine (550 ml) and THF (1.25 L) is treated with bis(triphenylphosphine)-palladium(II) chloride (10.1 g, 14.6 mmol) and copper(I) iodide (2.8 g, 14.6 mmol) under
Argon atmosphere at room temp., followed by dropwise addition of a solution of 1-ethynyl-4-pentylbenzene (CAS 79887-10-8) (125.0 g, 0.73 mol) in triethylamine (280 ml) at 0° C. The reaction mixture is stirred overnight at 0° C. and for 2 h at room temp. It is then filtered, washed with THF and concentrated i. vac. The residue is purified by silica gel chromatography (eluent petrol ether) to give 4-bromo-2-ethyl-1-((4-pentylphenyl)ethynyl)benzene as an orange oil.
A mixture of 4-bromo-2-ethyl-1-((4-pentylphenyl)ethynyl)benzene (123.7 g, 0.35 mol), bis(pinacolato)diboron (106.1 g, 0.42 mol) and potassium acetate (119.6 g, 1.23 mol) in dioxane (1.2 l) is treated with bis(tricyclohexylphosphine)palladium(II) chloride (9.5 g, 13.0 mmol) under Argon atmosphere at room temp., and the reaction mixture is stirred for 2 d at 80° C. It is then filtered (silica gel/Celite), washed with THF and concentrated i. vac. The residue is purified by silica gel chromatography (eluent petrol ether) and crystallization (acetone) to give 2-(3-ethyl-4-((4-pentylphenyl)ethynyl)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as light-yellow crystals.
A solution of sodium carbonate (19.8 g, 187 mmol) in dist. water (65 ml) is diluted with toluene (200 ml) and isopropanol (150 ml), treated with bis(triphenylphosphine)-palladium(II) chloride (5.0 g, 7.1 mmol) and hydrazine hydrate (2 drops) and stirred for 15 min under Argon atmosphere. Then, 5-bromo-1,3-difluoro-2-iodobenzene (CAS 160976-02-3) (23.8 g, 75 mmol) and 2-(3-ethyl-4-((4-pentylphenyl)ethynyl)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (25.0 g, 62 mmol) are added, and the reaction mixture is stirred for one week at 50° C. It is then filtered, washed with THF and concentrated i. vac. The residue is purified by silica gel chromatography (eluent petrol ether) and crystallization (petrol ether) to give 4-bromo-3′-ethyl-2,6-difluoro-4′-((4-pentylphenyl)ethynyl)-1,1′-biphenyl as a yellow solid.
Diisopropylamine (170 ml) is added to a solution of 4-bromo-3′-ethyl-2,6-difluoro-4′-((4-pentylphenyl)ethynyl)-1,1′-biphenyl (21.0 g, 45 mmol) and prop-2-yn-1-ol (2.8 g, 49 mmol) in THF (170 ml) at room temp. under Argon atmosphere, and the mixture is treated with X-Phos Pd Gen2 (71 mg, 0.09 mmol), di-tert-butyl X-Phos (38 mg, 0.09 mmol) and copper(I) iodide (9 mg, 0.05 mmol) at 60° C. The reaction mixture is stirred for 7 h at reflux temperature. Then it is cooled to room temp., filtered, washed with THF and concentrated i. vac. The residue is purified by silica gel chromatography (eluent petrol ether/MTB ether) and crystallization (petrol ether) to give 3-(3′-ethyl-2,6-difluoro-4′-((4-pentylphenyl)ethynyl)-[1,1′-biphenyl]-4-yl)prop-2-yn-1-ol as pale brown crystals.
A suspension of 3-(3′-ethyl-2,6-difluoro-4′-((4-pentylphenyl)ethynyl)-[1,1′-biphenyl]-4-yl)prop-2-yn-1-ol (17.8 g, 40 mmol) in acetonitrile (500 ml) is treated with a solution of ammonium acetate (12.4 g, 161 mmol) in dist. water (58 ml) at room temp. under Argon atmosphere, followed by subsequent addition of 2,2,6,6-tetramethylpiperidin-1-oxyl (0.3 g, 2 mmol) and (diacetoxyiodo)benzene (28.5 g, 88 mmol). The reaction mixture is stirred at room temp. for 4 h. It is then quenched with dist. water and MTB ether. The aqueous phase is separated and extracted with MTB ether, and the combined organic phases are washed with dist. water, dried (sodium sulfate) and concentrated i. vac. The crude product is purified by silica gel chromatography (eluent petrol ether) and crystallization (petrol ether) to give yellow crystals of 3-{3′-ethyl-2,6-difluoro-4′-[2-(4-pentylphenyl)ethynyl]-[1,1′-biphenyl]-4-yl}prop-2-ynenitrile.
Phase sequence: K 94 N 167 I.
In analogy to Synthesis Example 3, 3-{4′-[2-(2-ethyl-4-pentylphenyl)ethynyl]-2,6-difluoro-[1,1′-biphenyl]-4-yl}prop-2-ynenitrile is obtained:
Phase sequence: K 86 N 177 I.
Comparative Mixtures C1 and C2, and Mixture Examples M1 to M6 have the following compositions and properties.
Mixture Example M1 differs from Comparative Example C1 in that the compound PTU-4-AN is replaced with its isomer PTUI-4-AN according to the invention. This results in an improvement of all physical properties: an increased clearing temperature, a higher tunability, and lower dielectric loss which gives an improved material quality of 28 compared to only 25 of Comparative Example C1.
Mixture Example M2 differs from Comparative Example C2 in that the compound PTU-5-AN is replaced with its isomer PTUI-5-AN according to the invention. This results in an improvement of all physical properties: an increased clearing temperature, a higher tunability, and a lower dielectric loss which gives an improved material quality of 29 compared to only 26 of Comparative Example C2.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23208564 | Nov 2023 | EP | regional |
