Device for regulating the passage of light

Abstract

The present application relates to a device for regulating the passage of light which is characterised in that it comprises a layer comprising a liquid-crystalline mixture containing a characteristic structural element.

Claims

1. A window which is suitable for regulating the passage of light in the form of daylight from the environment into a space, said window containing a switching device for regulating the passage of light between a bright state and a dark state which does not comprise a polariser, said switching device comprising a layer which comprises a liquid-crystalline material comprising at least three different dye compounds, where the liquid-crystalline material has a clearing point of at least 95 C. and comprises at least one compound V which contains at least one unit selected from units of the formulae (E-1), (E-2) and (E-3), ##STR00162## where X is selected on each occurrence, identically or differently, from F, Cl, Br, I, CN, NCO, NCS, SCN, OCN, NC, CNO, CNS and N.sub.3; W is selected on each occurrence, identically or differently, from F, Cl, Br, I, CN, NCO, NCS, SCN, OCN, NC, CNO, CNS and N.sub.3; U is selected on each occurrence, identically or differently, from H, F, Cl, Br, I, CN, NCO, NCS, SCN, OCN, NC, CNO, CNS, N.sub.3, and alkyl, alkoxy or alkylthio groups having 1 to 10 C atoms, where one or more hydrogen atoms in the alkyl, alkoxy or alkylthio groups may be replaced by F or Cl, and where one or more CH.sub.2 groups in the alkyl, alkoxy or alkylthio groups may be replaced by O or S; dashed lines symbolise bonds to the remainder of the compound, and at least one group U per unit of the formula (E-3) is selected from F, Cl, Br, I, CN, NCO, NCS, SCN, OCN, NC, CNO, CNS and N.sub.3, and wherein the liquid-crystalline material additionally comprises one or more compounds which conform to the formula (F-1-2) ##STR00163## R.sup.11, R.sup.12 represent on each occurrence, identically or differently F, Cl, CN, NCS, SCN, R.sup.3OCO, R.sup.3COO or an alkyl or alkoxy group having 1 to 10 C atoms or an alkenyl or alkenyloxy group having 2 to 10 C atoms, where one or more hydrogen atoms in the above-mentioned groups may be replaced by F or Cl, and one or more CH.sub.2 groups may be replaced by O or S.

2. A window according to claim 1, wherein X is selected on each occurrence, identically or differently, from F and CN.

3. A window according to claim 1, wherein W is equal to CN.

4. A window according to claim 1, wherein U is selected on each occurrence, identically or differently, from H, F and CN.

5. A window according to claim 1, wherein the compound V contains precisely one unit selected from units of the formulae (E-1), (E-2) and (E-3).

6. A window according to claim 1, wherein the compound V has a structure of the following formula: ##STR00164## where R.sup.V1, R.sup.V2 represent on each occurrence, identically or differently, an alkyl or alkoxy group having 1 to 10 C atoms or an alkenyl or alkenyloxy group having 2 to 10 C atoms, where one or more hydrogen atoms in the above-mentioned groups may be replaced by F or Cl, and one or more CH.sub.2 groups may be replaced by O or S; ##STR00165## is selected on each occurrence, identically or differently, from the following groups: ##STR00166## or units of the formula (E-1), (E-2) or (E-3); Y is selected on each occurrence, identically or differently, from F, Cl, CN, and alkyl, alkoxy or alkylthio groups having 1 to 10 C atoms, where one or more hydrogen atoms in the alkyl, alkoxy or alkylthio groups may be replaced by F or Cl, and where one or more CH.sub.2 groups in the alkyl, alkoxy or alkylthio groups may be replaced by O or S; n is equal to 1, 2 or 3; and where at least one of the groups ##STR00167## is selected from units of the formula (E-1), (E-2) or (E-3).

7. A window according to claim 6, wherein the compound of the formula (V) contains precisely one unit selected from units of the formulae (E-1), (E-2) and (E-3).

8. A window according to claim 6, wherein the index n in formula (V) is equal to 1 or 2.

9. A window according to claim 6, wherein A.sup.V1 in formula (V) is selected on each occurrence, identically or differently, from ##STR00168## and units of the formulae (E-1-1a), (E-1-2a), (E-1-3a), (E-2-1) and (E-3-1) ##STR00169##

10. A window according to claim 1, wherein the liquid-crystalline material has a clearing point of at least 100 C.

11. A window according to claim 1, wherein the liquid-crystalline material has a dielectric anisotropy of 2 to 10.

12. A window according to claim 1, wherein the liquid-crystalline material comprises 5 to 15 compounds V, each having a different structure.

13. A window according to claim 1, wherein the liquid-crystalline material has a total proportion of compounds V of at least 40% by weight.

14. A window according to claim 1, wherein the liquid-crystalline material comprises compounds selected from compounds V which contain at least one unit of the formula (E-2), and compound(s) of the formula (F-1-2) in a total proportion of at least 10% by weight.

15. A window according to claim 1, wherein the liquid-crystalline material additionally comprises one or more compounds which conform to the formula (F-2), ##STR00170## where R.sup.21, R.sup.22 represent on each occurrence, identically or differently, F, Cl, CN, NCS, SCN, R.sup.3OCO, R.sup.3COO or an alkyl or alkoxy group having 1 to 10 C atoms or an alkenyl or alkenyloxy group having 2 to 10 C atoms, where one or more hydrogen atoms in the above-mentioned groups may be replaced by F or Cl, and one or more CH.sub.2 groups may be replaced by O or S; and R.sup.3 represents on each occurrence, identically or differently, an alkyl group having 1 to 10 C atoms, in which one or more hydrogen atoms may be replaced by F or Cl, and in which one or more CH.sub.2 groups may be replaced by O or S; Z.sup.21 is selected on each occurrence, identically or differently, from COO, OCO, CF.sub.2CF.sub.2, CF.sub.2O, OCF.sub.2, CH.sub.2CH.sub.2, CHCH, CFCF, CFCH, CHCF, CC, OCH.sub.2, CH.sub.2O and a single bond; and A.sup.21 is selected on each occurrence, identically or differently, from the following groups: ##STR00171## ##STR00172## ##STR00173## where Y is selected on each occurrence, identically or differently, from F, Cl, CN, and alkyl, alkoxy or alkylthio groups having 1 to 10 C atoms, where one or more hydrogen atoms in the alkyl, alkoxy or alkylthio groups may be replaced by F or Cl, and where one or more CH.sub.2 groups in the alkyl, alkoxy or alkylthio groups may be replaced by O or S.

16. A window according to claim 1, wherein the degree of anisotropy R of the dye compounds is greater than 0.4.

17. A window according to claim 1, wherein the dye compounds are selected from azo compounds, anthraquinones, methine compounds, azomethine compounds, merocyanine compounds, naphthoquinones, tetrazines, perylenes, terrylenes, quaterrylenes, higher rylenes, benzothiadiazoles, pyrromethenes and diketopyrrolopyrroles.

18. A window according to claim 1, which has an area extent of at least 0.5 m.sup.2.

19. A window according to claim 1, where the device is electrically switchable.

20. A window according to claim 1, where the device has the following layer sequence, where further layers may additionally be present: substrate layer electrically conductive transparent layer alignment layer switching layer comprising the liquid-crystalline material alignment layer electrically conductive transparent layer substrate layer.

21. A method comprising the step of including a liquid-crystalline material comprising at least three different dye compounds in a window suitable for regulating the passage of light in the form of daylight from the environment into a space, said window containing a switching device for regulating the passage of light between a bright state and a dark state, which does not comprise a polariser, where the liquid-crystalline material is incorporated in a layer of said switching device and has a clearing point of at least 95 C. and comprises at least one compound V as defined in claim 1 which contains at least one unit selected from units of the formulae (E-1), (E-2) and (E-3), as defined in claim 1.

Description

WORKING EXAMPLES

A) Preparation of Liquid-Crystalline Mixtures

(1) The two comparative mixtures V1 and V2 are prepared. Furthermore, the liquid-crystalline mixtures E1 to E10 are prepared, which are mixtures in accordance with the present application.

(2) The composition of mixtures V1, V2 and E1-E10 is indicated below. The chemical structures of the individual constituents of the mixtures are reproduced here by means of abbreviations (acronyms). These abbreviations are explicitly presented and explained in WO 2012/052100 (pp. 63-89), and consequently reference is made to the said application for explanation.

(3) The following abbreviations do not correspond to the said nomenclature, and consequently the corresponding chemical structures are shown explicitly.

(4) TABLE-US-00004 CCN-33 CCN-47 CCN-55 CCN-57 NCB-53 BCN-55 BCH-502F.N B-3-O2 0 B-2O-O5

(5) For the mixtures, the clearing point in degrees Celsius, the optical anisotropy n and the dielectric anisotropy are indicated. The 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. The value of n is determined at 589 nm and the value of is determined at 1 kHz.

(6) The low-temperature stability is determined in bottles and in test cells with a thickness of about 6 microns, in each case at room temperature (+20 C.) and at the temperatures 20 C., 30 C. and 40 C.

(7) The samples are subjected to a visual inspection for crystals or the formation of smectic phases at intervals of 24 h. The test is continued so long as crystals or smectic phases are not observed in the bottle or test cell at any of the said temperatures. As soon as crystals or smectic phases are observed, even in only one of the samples, the test is ended, and the number of days reached is indicated as low-temperature stability.

(8) TABLE-US-00005 TABLE 1 Mixture V1 V2 Clearing point in 91.5 79.5 C. 3.7 3.1 n 0.078 0.100 Low-temperature 8 days 42 days stability Composition CY-3-O2 12 CY-3-O2 12 CY-5-O2 12 CY-5-O2 13 CCY-3-O2 13 CCY-3-O2 11 CCY-5-O2 13 CCY-5-O2 10 CCY-3-1 8 CCY-2-1 9 CCZC-3-3 4 CPP-3-2 6 CCZC-3-5 3 CPP-5-2 4 CCZC-4-3 3 CGP-3-2 6 CC-3-4 6 CC-3-4 6 CC-3-5 6 CC-3-5 6 CC-3-O3 8 CP-3-O2 17 CC-5-O1 4 CC-5-O2 4 CP-3-O2 4

(9) TABLE-US-00006 TABLE 2 Mixture E1 E2 Clearing point in 100.5 106 C. 4.8 6 n 0.044 0.118 Low-temperature >42 days >73 days stability Composition CCN-47 20 CCN-33 10 CCN-55 21 CCN-47 10 CC-3-O1 11 CCN-57 10 CC-5-O1 5 CY-3-O2 5 CC-5-O2 5 NCB-53 13 CCZC-3-3 4 CCY-3-O2 5 CCZC-3-5 4 CCY-3-O3 5 CCZC-4-3 4 CCY-4-O2 6 CCZC-4-5 4 CPY-2-O2 9 BCN-55 22 CPY-3-O2 8 PYP-2-3 7 PYP-2-4 6 CGPC-3-3 2 CGPC-5-3 2 CGPC-5-5 2

(10) TABLE-US-00007 TABLE 3 Mixture E3 E4 Clearing point in 113.5 107.5 C. 6.0 4.9 n 0.127 0.103 Low-temperature >100 days >83 days stability Composition CCN-33 8 CCN-33 13 CCN-47 8 CCN-47 15 CCN-55 9 CCN-55 12 CY-3-O2 5 NCB-53 10 NCB-53 12 CPY-2-O2 5 CCY-3-O2 5 CPY-3-O2 5 CCY-3-O3 5 CCY-4-O2 5 CCY-4-O2 6 PYP-2-3 10 CPY-2-O2 9 CP-3-O1 8 CPY-3-O2 8 CGPC-3-3 4 PYP-2-3 7 CGPC-5-3 3 PYP-2-4 6 CGPC-5-5 3 CGPC-3-3 2 CCZPC-3-3 3 CGPC-5-3 2 CCZPC-3-4 2 CGPC-55 2 CCZPC-3-5 2 CPP-3-2 3 CPP-5-2 3

(11) TABLE-US-00008 TABLE 4 Mixture E5 E6 Clearing point in 111.5 107.5 C. 4.7 5.5 n 0.124 0.129 Low-temperature >73 days >73 days stability Composition CCN-47 10 CCN-33 8 CCN-55 10 CCN-47 10 CY-3-O2 6 CCN-55 10 CP-3-O1 10 CY-3-O2 10 NCB-53 10 BCH-502F.N 10 CPY-2-O2 7 CPY-2-O2 6 CPY-3-O2 7 CPY-3-O2 9 CCY-3-O2 6 CCY-4-O2 5 CCY-5-O2 7 PYP-2-3 10 PYP-2-3 10 PYP-2-4 10 CGP-3-2 6 CGPC-3-3 3 CGPC-3-3 3 CGPC-5-3 3 CGPC-5-3 3 CGPC-5-5 3 CGPC-5-5 2 CCZPC-3-3 3 CCZPC-3-3 3

(12) TABLE-US-00009 TABLE 5 Mixture E7 E8 Clearing point in 110.5 74 C. 4.9 3.5 n 0.132 0.101 Low-temperature >76 days 13 days stability Composition CY-3-O2 9 CC-3-V 41.5 CY-3-O4 9 CCY-3-O1 5 CY-5-O2 12 CCY-3-O2 11 CY-5-O4 8 CCY-4-O2 6 CCY-3-O2 5 CPY-2-O2 5 CCY-3-O3 5 CPY-3-O2 11 CCY-4-O2 5 CY-3-O2 3.5 CPY-2-O2 7 PY-3-O2 12 CPY-3-O2 6 B-3-O2 5 PYP-2-3 12 CCP-V-1 6 CCZPC-3-3 3 CCZPC-3-4 3 CGPC-3-3 5 CGPC-5-3 5

(13) TABLE-US-00010 TABLE 6 Mixture E9 E10 Clearing point in 74 87 C. 3.6 4.8 n 0.101 0.103 Low-temperature 15 days not det. stability Composition CC-3-V 40.5 CY-3-O2 12.5 CCY-3-O1 5 CCY-3-O1 9 CCY-3-O2 11 CCY-3-O2 11 CCY-4-O2 6 CCY-4-O2 7 CPY-2-O2 5.5 CPY-3-O2 3 CPY-3-O2 11 CC-3-V 31 CY-3-O2 5 B-2O-O5 4 PY-3-O2 12 PY-V2-O2 5.5 B-3-O2 4 CPY-V-O2 6 CPY-V-O4 5 CCY-V-O2 6

B) Preparation of Liquid-Crystalline Mixtures Comprising Dyes and Determination of their Physical Properties

(14) Of all mixtures E1-E10 shown under A), mixtures comprising one or more dyes are prepared. A representative selection of the results is shown below.

(15) B-1) Preparation of Mixtures Comprising the Dye F1 and Determination of Degree of Anisotropy and Solubility

(16) Mixtures comprising the dye F1 in one of the liquid-crystalline mixtures V1, E1, E2, E3 and E7 are prepared (composition see table below)

(17) ##STR00151##
Dye F1

(18) The degree of anisotropy R is determined from the value for the extinction coefficient E(p) (extinction coefficient of the mixture on parallel alignment of the molecules to the direction of polarisation of the light) and the value for the extinction coefficient of the mixture E(s) (extinction coefficient of the mixture on perpendicular alignment of the molecules to the direction of polarisation of the light), in each case at the wavelength of the maximum of the absorption band of the dye in question. If the dye has a plurality of absorption bands, the longest-wavelength absorption band is selected. The alignment of the molecules of the mixture is achieved by means of an alignment layer, as is known to the person skilled in the art in the area of LC devices. In order to eliminate the influences caused by liquid-crystalline medium, other absorptions and/or reflections, a measurement is in each case carried out against an identical mixture comprising no dye and the value obtained is subtracted.

(19) The measurement is carried out using linear-polarised light, whose direction of vibration is either parallel to the alignment direction (determination of E(p)) or perpendicular to the alignment direction (determination of E(s)). This can be achieved by means of a linear polariser, where the polariser is rotated against the device in order to achieve the two different directions of vibration. The measurement of E(p) and E(s) is thus carried out via the rotation of the direction of vibration of the incident polarised light. Alternatively, the sample can also be rotated against a spatially fixed direction of polarisation of the incident polarised light.

(20) The degree of anisotropy R is calculated from the values obtained for E(s) and E(p) in accordance with the formula
R=[E(p)E(s)]/[E(p)+2*E(s)],
as indicated, inter alia, in Polarized Light in Optics and Spectroscopy, D. S. Kliger et al., Academic Press, 1990. A detailed description of the method for the determination of the degree of anisotropy of liquid-crystalline media comprising a dichroic dye can be found in B. Bahadur, Liquid CrystalsApplications and Uses, Vol. 3, 1992, World Scientific Publishing, Section 11.4.2.

(21) The said method is employed identically in all following examples.

(22) TABLE-US-00011 Wavelength Liquid-crystal- Concentration of maximum Degree of line mixture Dye of the dye absorption anisotropy V1 (comp.) F1 0.25% by weight 504 nm 0.73 E1 F1 0.25% by weight 507 nm 0.74 E2 F1 0.25% by weight 507 nm 0.75 E3 F1 0.25% by weight 506 nm 0.75 E7 F1 0.25% by weight 505 nm 0.77

(23) The results show that the degree of anisotropy in the mixtures according to the invention is higher than in the comparative mixture.

(24) Furthermore, the solubility of the dye F1 in the various liquid-crystalline mixtures at +20 C. and 20 C. is investigated.

(25) TABLE-US-00012 Liquid-crystal- Maximum solubility line mixture Dye Temperature (observation after 1 week) V1 (comp.) F1 +20 C. 1.4% by weight V1 (comp.) F1 20 C. 0.9% by weight E1 F1 +20 C. 1.4% by weight E1 F1 20 C. 3.3% by weight E2 F1 +20 C. .sup.4% by weight E2 F1 20 C. .sup.4% by weight E7 F1 +20 C. 1.3% by weight E7 F1 20 C. 3.3% by weight

(26) It is found here that the solubility in the mixtures according to the invention is significantly higher than in the comparative mixture.

(27) B-2) Preparation of Mixtures Comprising the Dye F2 and Determination of Degree of Anisotropy and Solubility

(28) The procedure is as indicated in B-1).

(29) ##STR00152##
Dye F2

(30) TABLE-US-00013 Wavelength Liquid-crystal- Concentration of maximum Degree of line mixture Dye of the dye absorption anisotropy V1 (comp.) F2 0.25% by weight 615 nm 0.81 E2 F2 0.25% by weight 615 nm 0.80 E3 F2 0.25% by weight 617 nm 0.81 E7 F2 0.25% by weight 617 nm 0.81

(31) TABLE-US-00014 Liquid-crystal- Maximum solubility line mixture Dye Temperature (observation after 1 week) V1 (comp.) F2 +20 C. 2.0% by weight (1) V1 (comp.) F2 20 C. 1.8% by weight (1) E2 F2 +20 C. 2.6% by weight (1) E2 F2 20 C. 2.0% by weight (1) E3 F2 +20 C. 1.2% by weight (4) E3 F2 20 C. 1.8% by weight (4) E7 F2 +20 C. 1.4% by weight (12) E7 F2 20 C. 1.8% by weight (12)

(32) The results show that improved solubilities at the same time as comparable degrees of anisotropy are achieved with the liquid-crystalline mixtures according to the invention.

(33) B-3) Preparation of Mixtures Comprising the Dye F3 and Determination of Degree of Anisotropy and Solubility

(34) The procedure is as indicated in B-1).

(35) ##STR00153##
Dye F3

(36) TABLE-US-00015 Wavelength Liquid-crystal- Concentration of maximum Degree of line mixture Dye of the dye absorption anisotropy V1 (comp.) F3 0.25% by weight 613 nm 0.81 E2 F3 0.25% by weight 630 nm 0.78 E7 F3 0.25% by weight 617 nm 0.84

(37) TABLE-US-00016 Liquid-crystal- Maximum solubility line mixture Dye Temperature (observation after week) V1 (comp.) F3 +20 C. 0.8% by weight V1 (comp.) F3 20 C. 2.3% by weight E1 F3 +20 C. 3.9% by weight E1 F3 20 C. 4.0% by weight E2 F3 +20 C. 4.5% by weight E2 F3 20 C. 4.6% by weight E7 F3 +20 C. 4.1% by weight E7 F3 20 C. 4.1% by weight

(38) The results show that improved solubilities at the same time as comparable degrees of anisotropy are achieved with the liquid-crystalline mixtures according to the invention.

(39) B-4) Preparation of Mixtures Comprising the Dye F4 and Determination of Degree of Anisotropy and Solubility

(40) The procedure is as indicated in B-1).

(41) ##STR00154##
Dye F4

(42) TABLE-US-00017 Wavelength Liquid-crystal- Concentration of maximum Degree of line mixture Dye of the dye absorption anisotropy V1 (comp.) F4 0.25% by weight 630 nm 0.68 E3 F4 0.25% by weight 633 nm 0.68 E7 F4 0.25% by weight 631 nm 0.71

(43) The results show that comparable or better degrees of anisotropy are achieved with the liquid-crystalline mixtures according to the invention than with comparative mixture V1.

(44) B-5) Preparation of Mixtures Comprising the Dye F5 and Determination of Degree of Anisotropy and Solubility

(45) The procedure is as indicated in B-1).

(46) ##STR00155##
Dye F5

(47) TABLE-US-00018 Wavelength Liquid-crystal- Concentration of maximum Degree of line mixture Dye of the dye absorption anisotropy V1 (comp.) F5 0.25% by weight 539 nm 0.80 E3 F5 0.25% by weight 545 nm 0.80 E7 F5 0.25% by weight 543 nm 0.81

(48) The mixtures according to the invention exhibit equally good or better degrees of anisotropy as comparative mixture V1 for the dye F5.

(49) B-6) Preparation of Mixtures Comprising the Dye F6 and Determination of Degree of Anisotropy and Solubility

(50) The procedure is as indicated in B-1).

(51) ##STR00156##
Dye F6

(52) TABLE-US-00019 Wavelength Liquid-crystal- Concentration of maximum Degree of line mixture Dye of the dye absorption anisotropy V1 (comp.) F6 0.25% by weight 447 nm 0.81 E3 F6 0.25% by weight 453 nm 0.81 E7 F6 0.25% by weight 451 nm 0.81

(53) The example shows that the mixtures according to the invention have similar degrees of anisotropy as comparative mixture V1 for the dye F6.

(54) Similar values for degree of anisotropy and solubility of the dyes are obtained with comparative mixture V2 as for comparative mixture V1.

(55) The above examples show that liquid-crystalline mixtures comprising a wide variety of dyes can be prepared with the compounds according to the invention. The mixtures obtained are distinguished by high degrees of anisotropy and high solubility of the dye compounds at the same time as high solution stability and are thus highly suitable for use in devices for regulating the passage of light.

C) Use of Mixture E7 According to the Invention in a Device for Regulating the Passage of Light

(56) C-1) A mixture of liquid-crystalline mixture E7 and dyes F1 (0.10% by weight), F2 (0.23% by weight), F7 (0.09% by weight) and F8 (0.33% by weight) is prepared.

(57) ##STR00157##
Dye F7

(58) ##STR00158##
Dye F8

(59) The degree of anisotropy is determined for the mixture by the method indicated above. This is 0.8 over a broad range of the wavelength of the light from 430 nm to 630 nm.

(60) The liquid-crystalline material comprising the dyes is introduced into a device for regulating the passage of light. This has the following layer sequence: glass substrate layer electrically conductive transparent ITO layer, 200 ngstrm polyimide alignment layer, rubbed antiparallel switching layer comprising the liquid-crystalline material, 24.4 m polyimide alignment layer electrically conductive transparent ITO layer glass substrate layer

(61) In this arrangement, the liquid-crystalline material is in a planar alignment with antiparallel pretilt angle. This alignment is achieved by polyimide layers rubbed antiparallel to one another. The thickness of the liquid-crystal layer is controlled by spacers. The ITO layer is provided with electrical contacts, so that an electrical voltage can be applied via the switching layer comprising the liquid-crystalline material.

(62) Application of voltage enables colour-neutral switching of the device between dark (no voltage) and bright (voltage) to be achieved. The colour impression here is grey.

(63) The following values for the light transmissivity .sub.v are obtained for the device in the two switching states:

(64) .sub.v bright=84%

(65) .sub.v dark=49%.

(66) The light transmissivities .sub.v pale and .sub.v dark are calculated in accordance with European Standard EN410, equation (1) (Determination of luminous and solar characteristics of glazing). The light transmissivities .sub.v in accordance with this standard take into account the relative spectral distribution of the standard illuminant and the spectral brightness sensitivity of the standard observer.

(67) A further device according to the invention which comprises two switching layers is produced, as disclosed in the working examples of the as yet unpublished application EP13002445.8. The device has the following layer arrangement: glass layer ITO layer, 200 ngstrm polyimide alignment layer, rubbed antiparallel switching layer comprising the liquid-crystalline material, 24.4 m polyimide alignment layer, rubbed antiparallel ITO layer, 200 ngstrm glass layer layer sequence as for the above-mentioned 7 layers, rotated by 90 thereto about an axis perpendicular through the layers.

(68) The following values for the light transmissivity .sub.v are obtained for the device in the two switching states:

(69) .sub.v bright=71%

(70) .sub.v dark=11%.

(71) C-2) A mixture of liquid-crystalline mixture E7 and dyes F1 (0.103% by weight), F8 (0.287% by weight), F9 (0.101% by weight) and F10 (0.518% by weight) is prepared.

(72) ##STR00159##
Dye F9

(73) ##STR00160##
Dye F10

(74) A device for regulating the passage of light having a single switching layer is produced using this mixture, as indicated above under 1).

(75) The following values for the light transmissivity .sub.v are obtained for the device in the two switching states:

(76) .sub.v bright=81%

(77) .sub.v dark=47%.

(78) In addition, a device for regulating the passage of light having a double switching layer is produced using this mixture, as likewise indicated above under 1).

(79) The following values for the light transmissivity .sub.v are obtained for the device in the two switching states:

(80) .sub.v bright=66%

(81) .sub.v dark=10%.

(82) C-3) A mixture of liquid-crystalline mixture E7 and dyes F1 (0.048% by weight), F8 (0.223% by weight), F9 (0.116% by weight) and F11 (0.679% by weight) is prepared.

(83) ##STR00161##
Dye F11

(84) A device for regulating the passage of light having a single switching layer is produced using this mixture, as indicated above under 1).

(85) The following values for the light transmissivity .sub.v are obtained for the device in the two switching states:

(86) .sub.v bright=82%

(87) .sub.v dark=48%.

(88) In addition, a device for regulating the passage of light having a double switching layer is produced using this mixture, as likewise indicated above under 1).

(89) The following values for the light transmissivity .sub.v are obtained for the device in the two switching states:

(90) .sub.v bright=68%

(91) .sub.v dark=12%.