LIQUID CRYSTAL MEDIUM AND ELECTRONIC COMPONENT

Abstract

A liquid crystal medium comprising a) one or more compounds of formula I and one or more compounds of the formula T and one or more compounds of the formula S1

##STR00001##

and an electronic component comprising said LC medium, operable in the visible (VIS), infrared (IR) or microwave region of the electromagnetic spectrum. Also, the use of said LC medium in the IR, VIS or microwave region and to devices comprising said electronic component.

Claims

1. A liquid crystal medium comprising a) one or more compounds of formula I ##STR00278## in which R.sup.11 and R.sup.12, identically or differently, denote H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00279## and in which one or more H atoms may be replaced by fluorine, L.sup.11, L.sup.12, L.sup.13 identically or differently, denote H, CH.sub.3, Cl or F, A.sup.11 denotes phenylene-1,4-diyl, in which one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH.sub.3, CHF.sub.2, CH.sub.2F, CF.sub.3, OCH.sub.3, OCHF.sub.2 or OCF.sub.3, cyclohexane-1,4-diyl or cyclohexene-1,4-diyl, in which one or two non-adjacent CH.sub.2 groups may be replaced, independently of one another, by O and/or S and one or more H atoms may be replaced by F, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl, A.sup.12 denotes phenylene-1,4-diyl, in which one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH.sub.3, CHF.sub.2, CH.sub.2F, CF.sub.3, OCH.sub.3, OCHF.sub.2 or OCF.sub.3, or cyclohexane-1,4-diyl or cyclohexene-1,4-diyl, in which one or two non-adjacent CH.sub.2 groups may be replaced, independently of one another, by O and/or S and one or more H atoms may be replaced by F, Z.sup.1 denotes denote a single bond, CH.sub.2CH.sub.2, CH?CH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, CF?CF or CH?CHCH.sub.2O, n is 0 or 1; and b) one or more compounds of the formula T, ##STR00280## in which R.sup.1 and R.sup.2 denote H, F, Cl, Br, CN, SCN, NCS, SF.sub.5 or straight-chain alkyl having 1 to 12 C atoms or branched alkyl having 3 to 12 atoms, in which one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by CH?CH, C?C, O, CO, COO, OCO, or OCOO in such a way that 0 atoms are not linked directly to one another, and in which one or more H atoms may be replaced by F, Cl or Br, A.sup.T1, A.sup.T2 and A.sup.T3 each, independently of one another, denote phenylene-1,4-diyl, in which one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH.sub.3, CHF.sub.2, CH.sub.2F, CF.sub.3, OCH.sub.3, OCHF.sub.2 or OCF.sub.3, wherein A.sup.T1 alternatively denotes cyclohexane-1,4-diyl, in which one or two non-adjacent CH.sub.2 groups may be replaced, independently of one another, by O and/or S and one or more H atoms may be replaced by F, cyclohexene-1,4-diyl, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, tetrahydropyran-2,5-diyl or 1,3-dioxane-2,5-diyl, Z.sup.1 and Z.sup.2 each, independently of one another, denote CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2H.sub.4, C.sub.2F.sub.4, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, CFHCFH, CFHCH.sub.2, CH.sub.2CFH, CF.sub.2CFH, CFHCF.sub.2, CH?CH, CF?CH, CH?CF, CF?CF, C?C or a single bond, t is 0 or 1, and c) one or more compounds of formula S1 ##STR00281## in which R.sup.S1 and R.sup.S2, on each occurrence, identically or differently, denote H or straight-chain alkyl having from 1 to 25 carbon atoms or branched alkyl having from 3 to 25 carbon atoms, which are unsubstituted or monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen and in which one or more CH.sub.2 groups may each, independently of one another, be replaced by ##STR00282## O, S, CO, COO, OCO,OCOO, CH?CH or C?C in such a way that O and/or S atoms are not linked directly to one another, or halogen, aryl, heteroaryl, alkylaryl or arylalkyl having from 6, 5, 7, or 7 to 25 carbon atoms, respectively, each of which is unsubstituted or monosubstituted or polysubstituted by alkyl having from 1 to 6 C atoms or by halogen, s is 0, 1 or 2, and t is 0, 1, 2 or 3.

2. The liquid crystal medium according to claim 1, wherein the medium comprises one or more compounds selected from the group of compounds of the formulae S2 and S3 ##STR00283## in which q is 1, 2, 3 or 4, G denotes a hydrocarbon radical having from 1 to 60 carbon atoms, that can be straight chain or branched or cyclic, and which is unsubstituted or monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen and in which one or more CH.sub.2 groups may each, independently of one another, be replaced by O, S, NR.sup.o, CO, COO, OCO, OCOO, CH?CH or C?C in such a way that O or S atoms are not linked directly to one another, R.sup.0 denotes H or alkyl having 1 to 6 C atoms, R.sup.2 denotes H, O.Math., OH, straight chain alkyl or alkoxy having 1 to 12 C atoms or branched or cyclic alkyl having 3 to 25 C atoms or arylalkoxy having 7 to 25 C atoms, R.sup.21 and R.sup.22 identically or differently, denote a straight-chain alkyl having from 1 to 12 carbon atoms or branched alkyl having from 3 to 12 carbon atoms, or R.sup.21 and R.sup.22, together with the carbon atom to which they are attached, form a cycloalkyl group having from 5 to 12 carbon atoms, R.sup.23 and R.sup.24 identically or differently, denote a straight-chain alkyl having from 1 to 12 carbon atoms or branched alkyl having from 3 to 12 carbon atoms, or R.sup.23 and R.sup.24, together with the carbon atom to which they are attached, form a cycloalkyl group having from 5 to 12 carbon atoms, Z.sup.2 on each occurrence, identically or differently, denotes O, C(O)O, OC(O) or a single bond, R.sup.ST denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00284## and in which one or more H atoms may be replaced by fluorine, Z.sup.ST each, independently of one another, denote COO, OCO, CF.sub.20, OCF.sub.2, CH.sub.2O, OCH.sub.2, CH.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4-, CH?CHCH.sub.2O, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CF?CF, CH?CF, CF?CH, CH?CH, C?C or a single bond, ##STR00285## on each occurrence, identically or differently, denotes cyclohexane-1,4-diyl, cyclohexene-1,4-diyl, pyrane-2,5-diyl or 1,3-dioxane-2-5-diyl, in which one or more H atoms may be replaced by F, and p is 0, 1 or 2.

3. The liquid crystal medium according to claim 1, wherein the medium comprises one or more compounds of formula S2 selected from the group of compounds of the formulae S2-1 and S2-2 ##STR00286## in which G denotes a divalent aliphatic radical having 1 to 20 C atoms or a or cycloaliphatic radical having 3 to 20 C atoms.

4. The liquid crystal medium according to claim 1, wherein the medium comprises one or more compounds of formula I selected from the group of compounds of the formulae PT-1 to PT-3: ##STR00287##

5. The liquid crystal medium according to claim 1, wherein the medium comprises one or more compounds of the formula T selected from the group of compounds of the formulae T1 to T5, ##STR00288##

6. The liquid crystal medium according to claim 1, wherein the medium comprises one or more compounds of the formula S1 selected from the group of compounds of formula S1-1 ##STR00289## in which R.sup.S1 denotes H, F or Cl, and R.sup.21 and R.sup.22, identically or differently, denote H or straight-chain or branched alkyl having from 1 to 12 carbon atoms, in which one or more CH.sub.2 groups may each, independently of one another, be replaced by ##STR00290## O, COO, OCO, CH?CH or C?C in such a way that O atoms are not linked directly to one another, or aryl, or arylalkyl having from 6 to 25 carbon atoms.

7. The liquid crystal medium according to claim 1, wherein the medium further comprises one or more compounds selected from the group consisting of the formulae II and III: ##STR00291## in which R.sup.2 and R.sup.3 denote a straight-chain or branched alkyl or alkoxy radical that is unsubstituted or halogenated and has 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00292## C?C, CF.sub.2O, CH?CH, O, COO or OCO in such a way that O atoms are not linked directly to one another, ##STR00293## identically or differently, denote ##STR00294## L.sup.21, L.sup.22, L.sup.31 and L.sup.32 identically or differently, denote H or F, preferably F, Y.sup.2 and Y.sup.3 identically or differently, denote H or CH.sub.3, X.sup.2 and X.sup.3 identically or differently, denote halogen, halogenated alkyl or alkoxy with 1 to 3 C-atoms or halogenated alkenyl or alkenyloxy with 2 or 3 C-atoms, Z.sup.3 denotes CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, COO, trans- CH?CH, trans-CF?CF, CH.sub.2O or a single bond, and l, m, n and o are, independently of each other, 0 or 1.

8. The medium according to claim 1, wherein the medium further comprises one or more compounds of the formula IV ##STR00295## in which R.sup.41 denotes a straight chain alkyl radical having 1 to 12 C atoms or a branched or cyclic alkyl radical having 3 to 12 C atoms, or a straight chain alkenyl radical having 2 to 12 C atoms or a branched alkenyl radical having 3 to 12 C atoms or a cyclic alkenyl radical having 5 to 12 C atoms, wherein one or more H atoms are optionally replaced by fluorine, R.sup.42 denotes a straight chain alkyl or alkoxy radical having 1 to 12 C atoms or a branched or cyclic alkyl or alkoxy radical having 3 to 12 C atoms, or a straight chain alkenyl radical having 2 to 12 C atoms or a branched alkenyl radical having 3 to 12 C atoms or a cyclic alkenyl radical having 5 to 12 C atoms, wherein one or more H atoms are optionally replaced by fluorine.

9. The medium according to claim 8, wherein the medium comprises one or more compounds of formula IV selected from the group of compounds of the formulae IVa and IVb ##STR00296## in which R.sup.41 and R.sup.42, independently of one another, have the meanings defined in claim 8, and ##STR00297## Z.sup.4 denotes a single bond, CH.sub.2CH.sub.2, CH?CH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, C.sub.4H.sub.8, or CF?CF.

10. An electronic component comprising a first substrate and a second substrate facing each other, a liquid crystal medium sandwiched between said first and second substrates, an electrode provided on each substrate or two electrodes provided on only one of the substrates for supplying an electric potential across said liquid crystal medium to drive liquid crystals in a predetermined configuration, wherein said liquid crystal medium comprises the liquid crystal medium according to claim 1.

11. The electronic component according to claim 10, wherein the liquid crystal medium in the component is arranged as a tunable dielectric configured for use in high-frequency technology.

12. The electronic component according to claim 10, wherein the component is a liquid-crystal based antenna element, a phase shifter, a tunable filter, a tunable metamaterial structure, a matching network or a varactor.

13. A microwave antenna array, wherein it comprises one or more components according to claim 10.

14. The component according to claim 10, wherein the component is an optical component operable in the visible or infrared range of the electromagnetic spectrum.

15. The component according to claim 14, wherein the component is a transmissive spatial light modulator.

16. The component according to claim 14, wherein the component is a reflective spatial light modulator configured to modulate the phase of an incident optical signal propagating at least partially in a first dimension, wherein the first substrate is a transparent glass layer having a first, transparent electrode, and wherein the second substrate is a CMOS silicon backplane (160), the component further comprising a mirror (150) disposed between the second substrate and the liquid crystal medium, wherein the mirror is divided into a two-dimensional array of individually addressable pixels arranged and configured as second electrodes, each pixel being individually drivable by a voltage signal to provide a local phase change to at least one polarization component of an optical signal.

17. An optical device comprising an RGB light source, and the component according to claim 14, arranged and configured to modulate the phase of an incident optical signal from said RGB light source when the optical device is in operation.

18. A method of spatially modulating light, the method comprising, i) providing an optical component comprising first and second substrates facing each other and each having a surface, the first substrate comprising at least one first electrode, the second substrate comprising at least one second electrode, the component further comprising a liquid crystal layer sandwiched between the first and second substrates wherein the liquid crystal comprises the liquid crystal medium according to claim 1; ii) providing an RGB light source; ii) receiving incident light from said RGB light source at a surface of said optical component; iii) applying a predetermined voltage to each of the individual electrodes formed on the first substrate in order to modulate a refractive index of the liquid crystal layer.

Description

EXAMPLES

[0304] The following examples are intended to explain the invention without limiting it. Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. The following examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the following examples. From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

Mixture Example M1

[0305]

TABLE-US-00007 S1-1a 0.400% T.sub.(N, I). [? C.]: 101 PUQU-3-F 16.932% ?n (589.3 nm, 20? C.) 0.2467 APUQU-3-F 6.972% n.sub.e (589.3 nm, 20? C.) 1.7535 PGUQU-3-F 6.972% n.sub.o (589.3 nm, 20? C.) 1.5068 CC-3-V 14.940% ?? (1 kHz, 20? C.): 11.7 PPTUI-3-2 17.928% ?.sub.? (1 kHz, 20? C.): 15.1 PPTUI-3-4 17.928% ?.sub.? (1 kHz, 20? C.): 3.4 PUS-3-2 17.928% ?.sub.1 [mPa .Math. s], (20? C.): 177 ? 100.0% K.sub.1 [pN], (20? C.): 16.0 K.sub.3 [pN], (20? C.): 16.7 V.sub.0 [V], (20? C.): 1.24 LTS (bulk, 0? C.) >1000 h

Mixture Example M2

[0306]

TABLE-US-00008 S1-1a 0.400% T.sub.(N, I). [? C.]: 87.5 PUQU-3-F 16.932% ?n (589.3 nm, 20? C.) 0.2233 APUQU-3-F 6.972% n.sub.e (589.3 nm, 20? C.) 1.7272 PGUQU-3-F 6.972% n.sub.o (589.3 nm, 20? C.) 1.5039 CC-3-V 9.960% ?? (1 kHz, 20? C.): 10.7 CP-3-O2 14.940% ?.sub.? (1 kHz, 20? C.): 14.3 PPTUI-3-2 17.928% ?.sub.? (1 kHz, 20? C.): 3.6 PPTUI-3-4 16.932% ?.sub.1 [mPa .Math. s], (20? C.): 161 PUS-3-2 11.952% K.sub.1 [pN], (20? C.): 13.9 ? 100.0% K.sub.3 [pN], (20? C.): 15.8 V.sub.0 [V], (20? C.): 1.20 LTS (bulk, ?10? C.) >1000 h

Mixture Example M3

[0307] The medium M3 consists of 99.9% of the medium M1 and 0.1% of the compound S2-1a-1.

##STR00275##

Mixture Example M4

[0308] The medium M4 consists of 99.99% of the medium M1 and 0.01% of the compound S2-2a-1.

##STR00276##

Mixture Example M5

[0309] The medium M5 consists of 99.9% of the medium M2 and 0.1% of the compound S2-1a-1.

Mixture Example M6

[0310] The medium M4 consists of 99.99% of the medium M2 and 0.01% of the compound S2-2a-1.

[0311] A light stability test is performed with a H?nle LED Cube 100 IC using blue light with a peak wavelength of 460 nm and at an irradiance of 280 mW/cm.sup.2. The mixtures are irradiated in ITO cells coated with polyimide (AL3046 (CT19320)) with a cell gap of 6 ?m, and the VHR is measured at a temperature of 60? C. and a frequency of 60 Hz every 2 h. The results are shown in Table 1.

TABLE-US-00009 TABLE 1 VHR [%] (60? C., 60 Hz, 1 V) t = t = Mixture t = 0 h t = 2 h t = 4 h t = 6 h t = 8 h 10 h 12 h M1 99.3 94.7 91.2 88.0 87.3 87.4 86.7 M2 99.1 95.0 91.7 89.4 87.2 86.6 86.3 M3 99.6 99.2 98.7 98.3 97.9 97.6 97.3 M4 99.3 92.0 89.7 91.4 91.8 90.3 87.3 M5 99.6 99.3 98.8 97.9 97.0 96.6 95.9 M6 99.1 93.2 89.9 92.7 91.0 88.6 88.3

[0312] The mixtures M1 to M6 have excellent stability under irradiation with blue light. The VHR values are sufficiently high for applications in electronic devices.

[0313] Mixture example M7 contains the compound S3-3a

##STR00277##

Mixture Example M7

[0314]

TABLE-US-00010 S1-1a 0.44% T.sub.(N, I). [? C.]: 149 S3-3a 0.12% ?? (1 kHz, 20? C.): 4.9 PPTUI-3-2 19.89% ?.sub.? (1 kHz, 20? C.): 7.8 PPTUI-3-4 31.82% ?.sub.? (1 kHz, 20? C.): 2.9 CPGP-5-2 3.98% K.sub.1 [pN], (20? C.): 21.3 CPGP-5-3 3.98% K.sub.3 [pN], (20? C.): 23.3 PGUQU-3-F 3.48% V.sub.0 [V], (20? C.): 2.18 PGUQU-5-F 3.48% ?.sub.r, ? [20? C., 19 GHz]: 3.13 PUQU-3-F 2.98% tan ?.sub.? r, ? [20? C., 19 GHz]: 0.0034 CC-3-V 8.95% ?.sub.r, ? [20? C., 19 GHz]: 2.47 PUS-3-2 10.44% tan ?.sub.? r, ? [20? C., 19 GHz]: 0.0123 APUQU-3-F 2.98% ? [20? C., 19 GHz]: 0.211 CCP-V-1 7.46% ? [20? C., 19 GHz]: 17.1 ? 100.0%

[0315] The medium M7 has favorable properties for high frequency applications due to a low dielectric loss and high tunability.