Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/42—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
  • C09K19/44—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40 containing compounds with benzene rings directly linked
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/42—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
  • C09K19/46—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40 containing esters
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/07—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on electro-optical liquids exhibiting Kerr effect
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/137—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
  • G02F1/139—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
  • G02F1/1393—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K2323/00—Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1343—Electrodes
  • G02F1/134309—Electrodes characterised by their geometrical arrangement
  • G02F1/134363—Electrodes characterised by their geometrical arrangement for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]

Definitions

• Electro-optical light control element display and medium
• the present invention relates to light control elements and displays containing them.
• the light control elements preferably use control media which have anisotropic properties at certain temperatures, such as. B. liquid crystals.
• the light control elements are operated at a temperature at which the control media are in the isotropic phase.
• the present invention relates to an electro-optical light control element and to electro-optical displays and display systems containing such elements, such as, for example, television screens and computer monitors.
• the light control elements according to the invention contain a mesogenic control medium which is present in the isotropic phase during operation of the light control elements and, in addition to a good contrast and a low dependence on the viewing angle, are particularly distinguished by very short switching times.
• the present invention further relates to media and their use as control media in such light control elements.
• the first-mentioned displays are used in combination with a TFT (English: thin film transistor) control for displays with high information content and high resolution.
• TFT thin film transistor
• VAN displays are a variant of the ECB (electrically controlled birefringence) displays.
• MVA displays International: multi domain ertically aligned
• several domains are stabilized for each driven electrode and a special optical compensation layer is also used.
• these displays use an electric field which is vertical to the liquid crystal layer.
• IPS displays generally use electrodes on only one substrate, that is to say on one side of the liquid crystal layer, and are therefore characterized by an essential component of the electric field parallel to the liquid crystal layer.
• the present invention was based on the object of realizing particularly rapidly switching light control elements with good viewing angle dependency and the lowest possible control voltages.
• These light control elements should have the smallest possible layer thickness of the control media in order to be used as elements of FPDs (English: flat panel displays, i.e. flat displays), such as flat screens for Computer to be used.
• FPDs Terms: flat panel displays, i.e. flat displays
• they should be controllable by means of a simple electrode configuration and have a relatively low operating voltage.
• they should have a good contrast with a low viewing angle dependence for use in electro-optical displays.
• electro-optical Kerr effect is occasionally mentioned as an application of mesogenic media such as liquid crystals, among others in
• the present invention is a.
• Can produce medium be operated at a temperature at which the mesogenic medium is in the isotropic phase and
• the contrast of these displays and their viewing angle dependence are excellent.
• the switching times are extremely short and the control voltages only moderately high.
• the electric field used is preferably an inhomogeneous field.
• the mesogenic medium is used as the control medium for the light control element.
• mesogenic media are media which have a mesophase, which are soluble in a mesophase or which induce a mesophase.
• the mesophase is a smectic or, preferably, a nematic phase.
• the nematic mixture ZLI-4792 from Merck KGaA, Darmstadt, Germany is used as the preferred medium for investigating the mesogenic properties of the media which have no mesophase.
• the mesogenic media preferably have a clearing point of -100.degree. C. or more, particularly preferably of -50.degree. C. or more and very particularly preferably of -20.degree. C. or more, extrapolated from 10% solution in this mixture.
• the light control elements according to the invention preferably contain a mesogenic medium which is present in the isotropic phase at operating temperature. This medium is conveniently located on or under a substrate.
• the mesogenic medium is located between two substrates. If the mesogenic medium is between two substrates, at least one of these substrates is translucent.
• the translucent substrate, or the translucent substrates can, for. B. consist of glass, quartz or plastic. If a substrate is used that is not translucent, this can consist of a metal or a semiconductor, among other things. These media can be used as such or can be present on a carrier, for example a ceramic. If the mesogenic medium is a polymeric medium, the use of a second substrate can optionally be dispensed with. Polymeric mesogenic media can even be designed to be self-supporting. In this case, no substrate is required.
• the light control elements according to the invention contain an electrode structure which generates an electric field with a significant component parallel to the layer of the mesogenic medium.
• This electrode structure can be designed in the form of interdigital electrodes. It can be designed in the form of combs or ladders. Designs in the form of superimposed "H" s and double 'T's or Ts are also advantageous.
• the electrode structure is advantageously located on only one side of the mesogenic medium, if at least one substrate is used, preferably between this and the mesogenic medium.
• the electrode structure is preferably in at least two different planes, both of which are on one side of the mesogenic
• Control medium are present, this applies in particular if the electrode structure contains overlapping partial structures. These substructures are advantageously separated from one another by a dielectric layer. If the substructures are on the opposite sides of an insulation layer, a "layout" can be selected that allows capacitors to be implemented. This is particularly advantageous when controlling displays using an active matrix.
• Such active matrix displays use a matrix of control elements assigned to the individual light control elements with a non-linear current-voltage characteristic such as. B. TFTs or MIM (English: metal insulator metal) diodes.
• the electrodes can be made of transparent material, such as. B. Indium Tin Oxide (ITO). In this case, it may be advantageous and, if necessary, necessary to cover a part or parts of the light control element using a black mask. This allows areas where that electric field is not effective to shield and so improve the contrast.
• the electrodes can also be made of opaque material, usually metal. Then the use of a separate black mask can be omitted if necessary.
• the substructures of the electrode structure are located on the two opposite sides of the mesogenic medium.
• the corresponding parts of the electrodes are not perpendicular to one another, but are laterally offset from one another in such a way that a component of the electric field is created parallel to the layer of the mesogenic medium.
• the electrode structures are raised, that is to say they have a certain thickness, which cannot be neglected in relation to the layer thickness of the mesogenic medium.
• the electrode structures are raised, that is to say they have a certain thickness, which cannot be neglected in relation to the layer thickness of the mesogenic medium.
• Electrode structure have different topographies.
• the electrode structure can extend through a significant proportion of the total thickness of the layer of the mesogenic control medium.
• the maximum height of the electrode layer or the electrode layer is preferably significantly smaller than the thickness of the mesogenic medium.
• the ratio is preferably 1: 3 or less, particularly preferably 1:10 or less and very particularly 1:50 or less. In some cases the thickness of the electrode layer can be neglected compared to the thickness of the mesogenic medium, then the ratio is preferably 1: 100 or less.
• the operating temperature of the light control element is preferably above the transition temperature of the control medium to the isotropic phase, generally in the range from 0.1 ° to 50 ° above this transition temperature, preferably in the range from 0.5 ° to 10 ° above this transition temperature and particularly preferably in Range from 0.1 ° to 5 ° above this transition temperature.
• an orientation is induced in the mesogenic medium in the isotropic phase which leads to an optical one Delay leads, which can be visualized in a known manner.
• An inhomogeneous electric field is preferably used.
• the light control elements according to the invention contain at least one element for polarizing the light. In addition, they preferably contain a further optical element. This further optical element is either a second element for polarizing light, a reflector or a transflector.
• the optical elements are arranged such that the light passes through at least one polarizing element at least once when it passes through the mesogenic medium of the light control element both before it enters the mesogenic medium and after it exits the mesogenic medium.
• the mesogenic medium is located between two polarizers, ie a polarizer and an analyzer.
• Two linear polarizers are preferably used.
• the absorption axes of the polarizers are preferably crossed and preferably form an angle of 90 °.
• the light control element according to the invention optionally contains one or more birefringent layers. It preferably contains one ⁇ / 4 layer or several ⁇ / 4 layers, preferably one ⁇ / 4 layer.
• the optical delay of the ⁇ / 4 layer is preferably approximately 140 nm.
• the layer thickness (d) of the mesogenic control medium is preferably 0.1 ⁇ m to 5,000 ⁇ m (ie 5 mm), particularly preferably 0.5 ⁇ m to 1,000 ⁇ m (ie 1 mm), particularly preferably 1.0 ⁇ m to 100 ⁇ m and very particularly preferably 3.0 ⁇ m to 30 ⁇ m and in particular 3.5 ⁇ m to 20 ⁇ m.
• the layer thickness of the mesogenic control medium is preferably 0.5 ⁇ m to 50 ⁇ m, particularly preferably 1.0 ⁇ m to 20 ⁇ m and very particularly preferably 1.0 ⁇ m to 8.0 ⁇ m
• the light control element according to the invention can additionally contain one or more other conventional optical elements such as birefringent layers (eg compensation layers), diffuser layers, and elements for increasing the brightness and / or the light yield, the viewing angle dependence.
• birefringent layers eg compensation layers
• diffuser layers diffuser layers
• the light control elements according to the invention are characterized by a good contrast, which depends strongly and almost predominantly on the properties of the polarizers used.
• TN cells with an optical delay of 0.50 ⁇ m, positive contrast and the absorption axis of the polarizers perpendicular to the preferred orientation of the nematic liquid crystals on the adjacent substrate, which contain non-chiral liquid crystals, are used here. If the same polarizers are used in the light control elements according to the invention and in these conventional TN cells, the contrast of the light control elements according to the invention is 40% or more greater than that of the TN cells.
• An isocontrast curve of a given contrast ratio in the light control elements according to the invention generally includes an angular range which is more than twice as large, often even more than three times as large as the corresponding isocontrast curve for the same contrast ratio in the TN display.
• the switching times of the light control elements according to the invention are very short. They are generally values of 1 ms or less, preferably 0.5 ms or less, particularly preferably 0.1 ms or less.
• the light control elements according to the invention were each switched, for example, from the voltage V-io to V9 0 , V 8 o, V 70 to V_o, so the switch-on time is from the time the new voltage is switched on until it is reached 90% of the respective maximum transmission change for all of these switching processes is identical in all cases in a first approximation.
• Electro-optical displays according to the present invention contain one or more light control elements according to the invention. In a preferred embodiment, these are controlled by means of an active matrix.
• the light control elements according to the invention are actuated in the so-called “field sequential mode”.
• the switching elements are successively illuminated with differently colored light in synchronism with the actuation or flash lamps are used.
• Electro-optical displays according to the present invention can contain a color filter for displaying colored images.
• This color filter expediently consists of a mosaic of filter elements of different colors.
• An element of the color filter mosaic of a color is typically assigned to each electro-optical switching element.
• the mesogenic media according to the present invention preferably have a nematic phase.
• media can be used in which the temperature range of the nematic The phase is so narrow that there is practically a transition from the crystalline phase or from the smectic phase to the isotropic phase.
• the clearing point of the mesogenic media having a nematic phase is preferably in the range from -20 ° C. to 80 ° C., particularly preferably in the range from 0 ° C. to 60 ° C. and very particularly preferably in the range from 20 ° C. to 60 ° C.
• the clearing point is preferably in the range of 10 ° C to 70 ° C and particularly preferably in the range of 30 ° C to 50 ° C.
• the nematic phase is preferably stable to -10 ° C, particularly preferably to -30 ° C and very particularly preferably to -40 ° C.
• the mesogenic media according to the present invention preferably have a birefringence ( ⁇ n) of 0.100 or more, particularly preferably of 0.150 or more, very particularly preferably of 0.200 or more in the nematic phase at a temperature of 4 degrees below the clearing point.
• ⁇ n birefringence
• the value of the birefringence is virtually unlimited for the application according to the invention. In practice, however, it is usually 0.500 or less and usually 0.450 or less.
• the value of the birefringence of the media according to the invention is measured here in the nematic phase at a temperature of 4 ° below the clearing point.
• the birefringence of a mixture of 15% of the medium and 85% of the nematic mixture ZLI-4792 from Merck KGaA is determined at 20 ° C and extrapolated from the change compared to mixture ZLI-4792 to the value of the pure medium.
• the mesogenic media according to the present invention preferably have a dipole moment of 4 debye or more, particularly preferably 6 debye or more and particularly preferably 8 debye or more.
• Both mesogenic control media that are in the mesophase can be used for the light control elements according to the present invention have a positive dielectric anisotropy ( ⁇ ), as well as those which have a negative dielectric anisotropy.
• Mesogenic control media are preferably used which have a positive dielectric anisotropy ( ⁇ ) in the mesophase.
• the mesogenic control media have a positive dielectric anisotropy, this, at kHz and a temperature of 4 ° below the clearing point, preferably in the nematic phase, has a value of preferably 15 or more, particularly preferably 30 or more and very particularly preferably 45 or more. If the medium has no nematic phase or if it is not in the nematic phase at a temperature of 4 ° below the clearing point, its dielectric anisotropy, like birefringence, is determined by extrapolation of the values of a mixture of 15% in the mixture ZLI-4792.
• the mesogenic control media have a negative dielectric anisotropy, this has a value of preferably -5 or less, particularly preferably -7 or less and very particularly preferably -10 or less.
• Control media with a positive dielectric anisotropy are particularly preferred.
• the mesogenic media according to the present invention preferably consist of two to 40 compounds, particularly preferably five to 30 compounds and very particularly preferably seven to 25 compounds.
• the mesogenic media according to the invention with positive dielectric anisotropy according to the present invention preferably contain
• a component A consisting of one or more compounds with a very strongly positive dielectric anisotropy of 30 or more
• a component B consisting of one or more compounds with a highly positive dielectric anisotropy of 10 to ⁇ 30
• a component C consisting of one or more
• a component D consisting of one or more dielectric neutral connections with a dielectric
• a component E consisting of one or more compounds with a negative dielectric anisotropy of less than -1.5.
• Component A of these media preferably contains one or more compounds of the formula I and particularly preferably consists predominantly and very particularly preferably almost completely of one or more compounds of the formula I.
• R 1 n-alkyl, n-alkoxy each having 1 to 7 C atoms, alkenyl, alkenyloxy, alkynyl or alkoxyalkyl each having 2 to 7 C atoms,
• Z 11 and Z 12 are each independent of one another, a single bond
• the media according to the invention preferably contain one or more compounds selected from the group of compounds of the formulas
• the media according to the invention particularly preferably comprise one or more compounds selected from the group of the compounds of the formulas 1-1 a to 1-1 e, l-2a to l-2c, l-3a to l-3c, l-4a to l- 4c, l-5a to l-5c, I-6a to l-6c and l-7a to I-7c and / or one or more compounds selected from the group of the compounds of the formulas 11-1 a to 11-1 c, ll-2a to ll-2c, ll-3a, Il3b, ll-3a, ll-4b, ll-5a and ll-5b.
• the compounds of the formulas 1-1 a to 1-1 e are preferably selected from the group of compounds of the formulas 1-1 a-1 to 1-1 a-6, 1-1 b-1 to 1-1 b-9 , 1-1 c-1 to 1-1 c-9, 1-1 d-1 to 1-1 d-5 and 1-1 e-1 and 1-1 e-2.
• n is an integer from 0 to 7, preferably 1 to 7
• m is an integer from 0 to 5
• n + m is an integer from 0 to 7, preferably from 1 to 5.
• the compounds of the formulas I-2a to I-2c are preferably selected from the group of the compounds of the formulas I-2a-1 to I-2a-5, I-2b-1 to I-2b-9 and I-2c-1 to l-2c-17.
• n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5
• m is an integer from 0 to 5
• n + m is an integer from 0 to 7, preferably from 1 to 5.
• the compounds of the formulas I-3a to I-3c are preferably selected from the group of the compounds of the formulas I-3a-1 to I-3a-4, I-3b-1 to I-3b-4 and I-3c-1 to l-3c-4.
• n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.
• the compounds of the formulas I-4a to I-4c are preferably selected from the group of the compounds of the formulas I-4a-1 to I-4a-3, I-4b-1 to I-4b-3 and I-4c-1 to l-4c-3.
• n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.
• the compounds of the formulas I-5a to I-5c are preferably selected from the group of the compounds of the formulas I-5a-1b to I-5a-3, I-5b-1 to I-5b-3 and I-5c- 1 to l-5a-1 l-5ca-3.
• n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.
• the compounds of the formulas I-6a to I-6c are preferably selected from the group of the compounds of the formulas I-6a-1 to I-6a-3, I-6b-1 to I-6a-3 and I-6c-1 to l-6a-3.
• n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.
• the compounds of the formulas I-7a to I-7c are preferably selected from the group of the compounds of the formulas I-7a-1 and I-7a-2, I-7b-1 and I-7b-2 and I-7c-1 and l-7c-2.
• n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.
• the media according to the invention particularly preferably comprise one or more compounds selected from the group of the compounds of the formulas 11-1c-1, ll-2c-1, ll-3b-1, ll-4b-1 and Il-5b-1.
• n is an integer from 0 to 7, preferably from 0 to 5 and particularly preferably from 1 to 5.
• the media according to the invention preferably contain one or more
• the mesogenic media according to the present invention with positive dielectric anisotropy particularly preferably consist predominantly and very particularly preferably almost entirely of component A.
• the mesogenic media according to the present invention with positive dielectric anisotropy contain one or more components selected from the group of components B to D, preferably selected from the group of components B and D.
• Component D of these media preferably contains one or more compounds.
• the mesogenic media with negative dielectric anisotropy according to the present invention preferably contain
• component B 1 consisting of one or more compounds with a moderately negative dielectric anisotropy of -1.5 to ⁇ -5,
• a component C consisting of one or more dielectric neutral compounds with a dielectric anisotropy of -1, 5 to +1, 5 and
• the mesogenic medium according to the present invention can contain further additives and chiral dopants in conventional concentrations.
• the total concentration of these further constituents is in the range from 0% to 10%, preferably in the range from 0.1% to 6%, based on the total mixture.
• the concentrations of the individual of these compounds are in the range from 0.1 to 3%.
• the concentration of these compounds and similar components of the mixture are not taken into account when specifying the concentration ranges of the other components of the mixture.
• the media are obtained from the compounds in the usual way.
• the compounds which are used in a smaller amount are expediently dissolved in the compounds used in a larger amount. If the temperature is raised above the clearing point of the predominant component during the mixing process, the completeness of the dissolution can easily be observed.
• the media according to the invention can also be produced in other ways. So through the use of premixes. Among other things, homolog mixtures and / or eutectic mixtures can be used as premixes. The premixes can, however, also be ready-to-use media themselves. This is the case with so-called two-bottle or multi-bottle systems. )
• Dielectric positive connections have a ⁇ > 1, 5, dielectric neutral connections have a ⁇ in the range -1, 5 ⁇ ⁇ 1, 5 and dielectrically negative connections have a ⁇ ⁇ -1, 5.
• dielectrically negative connections have a ⁇ ⁇ -1, 5.
• the dielectric anisotropy ⁇ of the compounds is determined at 1 kHz and 20 ° C. by extrapolation of the values of a 10% solution of the respective compound in a host mixture to a proportion of the respective
• connection determined by 100%.
• the capacities of the test mixtures are determined both in a cell with a homeotropic and in a cell with a homogeneous edge orientation.
• the layer thickness of both cell types is approximately 20 ⁇ m.
• a square wave with a frequency of 1 kHz and an effective voltage (rms, English: root mean square) of typically 0.2 V to 1.0 V is used for the measurement. In In any case, the voltage used is lower than the capacitive threshold of the mixture examined.
• the mixture ZLI-4792 is used for dielectric positive connections and for dielectric neutral connections, as well as for dielectric negative connections
• threshold voltage means to the optical threshold and is given for a relative contrast of 10% (V 1 0).
• the mid-gray voltage and the saturation voltage are also determined optically and specified for a relative contrast of 50% and 90%, respectively.
• the capacitive threshold voltage (Vo), also called the Freedericksz threshold, is given, so this is explicitly stated.
• the specified ranges of values include the limit values.
• the concentrations are given in mass% and relate to the complete mixture. Temperatures are given in degrees Celsius and temperature differences in degrees Celsius. All physical properties were determined as in "Merck Liquid Crystals, Physical Properties of Liquid Crystals", as of November 1997, Merck KGaA, Germany and are stated for a temperature of 20 ° C.
• the optical anisotropy ( ⁇ n) also called birefringence, is determined at a wavelength of 589.3 nm.
• the dielectric anisotropy ( ⁇ ) is determined at a frequency of 1 kHz.
• Material in the reference unit is preferably 50% or more, particularly preferably 60% or more and very particularly preferably 70% or more and
• the concentration of the material mentioned in the reference unit is preferably 80% or more, particularly preferably 90% or more and very particularly preferably 95% or more.
• the dielectric properties, electro-optical properties (eg the threshold voltages) and the switching times were determined in test cells manufactured by Merck KGaA, Darmstadt, Germany.
• the test cells for determining ⁇ had a layer thickness of 22 ⁇ m and a circular electrode made of indium tin oxide (ITO) with an area of 1.13 cm 2 and a protective ring.
• ITO indium tin oxide
• cells with a homeotropically oriented polyimide orientation layer were used.
• lecithin (Merck KGaA) can be used as an orientation aid.
• the cells for determining ⁇ i had orientation layers made of the polyimide AL-1054 from Japan Synthetic Rubber, Japan.
• Table B Alkyl groups with n or m carbon atoms.
• Table B is self-explanatory, since it gives the full abbreviation for a formula of homologous compounds.
• Table A shows only the abbreviations for the core structures of the connection types.
• the abbreviations for the individual compounds are composed of the applicable abbreviations for the core of the compound and the abbreviation for the groups R, R 2 , L 1 and L 2 attached by means of a hyphen according to the following table.
• the mesogenic media according to the present application preferably contain
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• An electro-optical test cell with a light switching element containing the liquid crystal mixture was produced.
• the substrates were made of glass. Substrates without an orientation layer were used.
• the electrode structure consisted of interdigitated comb-shaped electrodes. The width of the electrodes was 20 ⁇ m and the distance between the
• Electrodes from each other was 10 ⁇ m.
• the layer thickness of the electrodes was 60 nm.
• the electrodes were all in a common plane.
• the layer thickness of the control medium was 6.8 ⁇ m.
• a first polarizer was used in front and a second polarizer (analyzer) behind the cell.
• the absorption axes of the two polarizers formed an angle of 90 ° to one another.
• the angle between the axis of maximum absorption of the polarizers and the component of the electric field in the plane of the display was 45 ° in each case.
• Voltage transmission characteristic was determined with an electro-optical measuring station DMS 703 from Autronc-Melchers, Karlruhe, Germany. The operating temperature was 24.0 ° C. With vertical
• V 10 the threshold voltage
• V 50 the value of the medium gray voltage
• V 90 the value of the saturation voltage
• a liquid crystal mixture of the following composition was prepared.
• an electro-optical display was implemented and its characteristic was measured.
• the temperature was 26.5 ° C.
• the characteristic curve is shown in Figure 1.
• the characteristic begins at a low voltage with a relative intensity of 0% and increases with increasing voltage.
• the value of the threshold voltage (V 10 ) was 34 V
• the value of the medium gray voltage (V 50 ) was 53 V
• the value of the saturation voltage (Vg . ) was 64 V.
• V 10 the threshold voltage
• V 50 the value of the medium gray voltage
• Vg . the saturation voltage
• the relative intensity drops to a value of approx. 14% at a voltage of 130 V.
• the relative intensity increases again.
• a voltage of 200 V a relative intensity of 65% is reached again.
• the switching times of the cells were also measured with the DMS 703.
• the standard high-frequency filter was switched off due to the small values of the switching times.
• both the switching time for switching off and the switching on are less than 50 ⁇ s.
• the cell was each from the voltage V 10 to Vg 0 , V 80 , V 5 o and V 2 o, from V 2 o to Vgo, V 8 o, and from V 50 to Vgo and V 8 o and from V ⁇ o switched to Vg.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• an electro-optical display was implemented and its characteristic was measured.
• the temperature was 23.1 ° C.
• the characteristic curve of this example is shifted to significantly lower voltages.
• the value of the threshold voltage (V ⁇ 0) was 36.5 V, the value of the mid-gray voltage (V 5 o) at 55 V and the value of the saturation voltage (Vg 0) at 61, 5 V.
• the maximum was 65 V and the Minimum at 83 V and approx. 32% relative
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• an electro-optical display was implemented and its characteristic was measured.
• the temperature was 23.5 ° C.
• the increasing part of the characteristic curve for small voltages for this example lies at voltages between those of examples 2 and 3.
• the maximum was 72 V and the minimum was 123 V and 19% relative intensity. At a voltage of 200 V, a relative intensity of approx. 74% was achieved.
• a conventional TN display cell was made.
• the liquid crystal material used was MLC-6873-100 from Merck KGaA.
• the optical delay was 0.50 ⁇ m.
• Isocontrast curves were measured as described in Example 4.
• the TN display was switched from a voltage of 0 V to 2.36 V, twice the threshold voltage. The results are shown in Figure 3.
• the maximum contrast occurred when viewed vertically.
• the maximum contrast ratio was only 29.9.
• the minimum contrast ratio was only 1.0. Under these control conditions, an inverse contrast did not occur even with the TN display. This already shows the overall lower contrast compared to Figure 2 of Example 4, as well as the significantly greater dependence of the contrast on the viewing angle.
• the isocontrast curves in the illustration show the course for contrast ratios of 20, 15, 10, 7, 5, 3, and 2 from the inside to the outside.
• the curves are not center symmetrical here. They are also much closer together than in Figure 2 in Example 4. So the viewing angle dependence of the contrast in this comparative example is much stronger here than in Example 4. Further examples of mesogenic control media according to the invention are given below.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared. Connection / abbreviation concentration / mass%
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared. Connection / abbreviation concentration / mass%
• This mixture has the following properties. ⁇ (20 ° C, 1 kHz)> 0
• a liquid crystal mixture of the following composition was prepared.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• a liquid crystal mixture of the following composition was prepared.
• a liquid crystal mixture of the following composition was prepared.
• This mixture has the following properties.
• Figure 1 The figure shows the transmission voltage characteristic of the light control element of example 2. Relative intensities are shown as a function of the rms voltage values in volts.
• Figure 2 The figure shows the contrast ratios of the light control element of Example 4 according to the invention
• Measurement conditions especially the operating voltages, are described in the text.
• the display is in polar coordinates.
• the lines from inside to outside show the gradients for contrast ratios of 30, 20, 15 and 10.
• the maximum contrast ratio of 36.8 was at vertical
• Figure 3 The figure shows the contrast ratios of the light control element in the comparative example.
• the measurement conditions, especially the operating voltages, are described in the text.
• the display is in polar coordinates.
• the lines show the gradients for contrast ratios of 20, 15, 10, 7, 5, 3, and 2 from inside to outside.
• the maximum contrast was 29.9 and the minimum 1.0.

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