KR20150030168A - Liquid-crystalline media, switchable liquid crystal lenses and liquid crystal displays comprising these - Google Patents

Abstract

The present invention relates to a liquid crystal medium including at least one of each compound of chemical formula I and II, and to a method for manufacturing the same. Here, variables have meanings disclosed in claims or the specification respectively. The present invention also relates to usage of the liquid crystal medium in a 3D lens and a 3D lens containing liquid crystal medium according to the present invention. The lens is proper especially to an auto-stereoscopic 3D display, and the display is also a part of the present invention.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal medium, a switchable liquid crystal lens, and a liquid crystal display including the liquid crystal medium,

The present invention relates to a liquid crystal medium for a liquid crystal switching lens, in particular, a liquid crystal display capable of displaying 3D images. Such a liquid crystal switching lens uses a specific liquid crystal medium for an LC lens that is based on electrically induced birefringence and can be electrically switched. The present invention also relates to the use of a novel liquid crystal medium and a liquid crystal switching lens.

BACKGROUND ART Various types of liquid crystal displays (LCDs) are widely known and widely used in the market. In recent years, the demand for display images to provide observers with a natural viewing experience has been increasing, not only in TV sets, but also in monitors for desktop and laptop computers, and even in small devices such as mobile phones, tablet computers, (I. E., 3D) images. ≪ / RTI >

In recent years, several techniques have been used to provide 3D effects for such displays. In the first classification, a number of different techniques that require observers to wear special glasses to observe 3D effects can be distinguished from other techniques using auto-stereoscopic display principles. In the latter, observers do not need to wear glasses, regardless of active or passive type of glasses.

Some observers are looking for the need to wear less uncomfortable glasses. Especially observers already wearing optical (i.e., ophthalmic) glasses.

Another disadvantage of 3D providing techniques that require glasses is that such observations are completely impossible without glasses, and therefore the maximum number of viewers who can view the display at the same time is limited by the number of glasses available at a time. In addition, the surface of the glasses is liable to be degraded. Also, last but not least, in the case of active glasses that require active and synchronized operation of the glasses as a shutter or polarization modifier at a timing matched with the panel displaying the image, it is necessary to constantly provide a tuning signal to the glasses . Also, unless you provide an energy supply by connecting wires to the observer, you need to charge your battery frequently, and in most cases these latter alternatives are less attractive. Nowadays, due to several serious drawbacks of various types of 3D technology that observers need to wear special glasses, there is a great demand for displays that can provide 3D images without the need for glasses.

This "glass-free" 3D technique is called auto-stereoscopic display. At present, two or more distinctly different types of such displays are being developed.

A first type of this technique is to implement a so-called "parallax barrie" to distinguish features shown by the right eye and the left eye, provided by two separate channels of each information .

This parallax barrier blocks the optical path of the field of view produced by the remaining eyes, for each eye.

The second type uses "lenticular lenses" to achieve this separation effect of the two channels. Again in this second type of case, there are two different ways to realize realization.

In the first case, referred to herein as an "RM " lens, a lenticular lens is realized by polymerizing a mixture of oriented reactive mesogens or reactive mesogens to form an anisotropic liquid crystal polymer lens. However, this technique requires the use of additional electro-optic switching elements (e.g., liquid crystal displays) to provide information about the optical image. This again leads to increased design complexity and increased production costs.

If a 2D image is converted to a 3D image, or vice versa, to attach a 3D lens, an additional process is required to optically couple such a 3D lens to the polarization switching panel, typically using UV radiation. Therefore, UV stability of the LC medium is very important in many applications. The polarization switching panel, together with the combined RM lens, is typically attached directly to an image generating panel (preferably an LCD).

In the second case, referred to herein as "LC lens, " a lenticular lens is created using a liquid crystal medium, the lens itself is electrically addressed and changes its optical state to directly display the optical information required for the two viewing channels The lens itself is used.

Such an LC lens is typically directly coupled to the image generation panel.

The primary variable of the LC mixture for a switchable 3D LC lens is? N because it primarily affects the quality (depth) of the 3D image and determines the required cell spacing. As Δn increases, the 3D depth becomes deeper and the cell spacing used can be lower. This reduced cell spacing helps both to reduce the drive voltage and to increase the orientation force, especially in the case of relatively high cell spacing of several tens of micrometers. Generally, a value of DELTA n in the range of 0.15 to 0.4 is required depending on the type and application.

For the "LC lens" type, there are also two possible embodiments. In the first case, referred to herein as a "polymeric mold ", the liquid crystal material is embedded in a mold of a polymeric material. These polymeric materials (which may be optically isotropic or anisotropic) are typically present in one of the substrates. These polymeric materials are structured in such a way as to provide space for liquid crystal material in an inverse form of the lenticular lens to be realized. Typically, the polymeric material forms a trough of an inverted lenticular lens.

The second case, referred to herein as " electrically induced birefringence "(short EIB), involves a liquid crystal material interposed between a pair of substrates (one of which is coated with an electrode) Quot; switching "(IPS) display or" fringe field switching "(FFS).

At first glance, a 3D lens of the LC lens type appears to be a simpler and simpler element, but in order to realize this realistically, some serious difficulties associated with the driving technology and manufacturing method must be overcome. In addition, the liquid crystal material should be improved and the more burdensome specifications must be satisfied. In the present application, a liquid crystal medium with improved performance for a switchable 3D LC lens is proposed.

In the plastic mold type, the LC material is embedded into the mold. An LC lens of this type is essentially required to have a relatively high value [Delta] n of approximately 0.2 to 0.4. In addition, a high dielectric constant (DELTA epsilon) value of 40 or more is typically required to reduce the operating voltage caused by each cell spacing of a relatively large thickness. In addition, only moderately high rotational viscosity? 1 is required.

In the EIB type, the orientation of the LC molecules is directly controlled by the applied voltage. Therefore, an extremely high value [Delta] n is not required. Typically, the value of [Delta] n should range from 0.15 to 0.25. Also, large cell spacing is not required. Thus, for this type of LC lens, a moderately high amount of DELTA epsilon value of 5 or less is sufficient. However, especially for devices with multiple viewpoints, a low? 1? Value is required to achieve a fast response time?.

The UV stability of the LC medium used is very important in many applications, as is typically the case in manufacturing processes in which UV irradiation is applied.

The LC compositions known hitherto have serious disadvantages in applications related to the present invention. Most of these compositions offer not only other defects but also inadequate addressing ability and / or inadequate stability, especially for UV radiation, which require an unfavorably small adjustment and / or slow response of the optical response and / or high operating voltage.

Thus, there is a need for new liquid crystal media with improved properties. In particular, the adjustment of the optical response, response time, operating voltage and safety must be improved.

In addition, improvement of the low-temperature behavior of the liquid crystal medium is required. Now, improvements in both operating characteristics and shelf life are needed.

Therefore, there is a great need for a liquid crystal medium having properties suitable for the corresponding practical use.

Surprisingly, it has been found possible to achieve a component for a high-frequency technology that has no, or at least substantially reduced, disadvantages of the preceding materials when using selected liquid crystal media.

Surprisingly it has now surprisingly been found that the mesogenic medium comprising the following can be advantageously used for the preparation of a composition which has an acceptable high point of cleavage, a suitably high birefringence, a suitable dielectric anisotropy, and / It has been found that it is possible to realize a medium having high stability:

- one or more compounds of formula (I)

In this formula,

R ¹ is preferably straight or branched chain alkyl having 1 to 20 carbon atoms which is unsubstituted or mono- or multiply substituted with F, Cl or CN, preferably F, wherein one or more CH ₂ groups, in each case, Independently of one another, -O-, -S-, -NR ⁰¹ -, -SiR ⁰¹ R ⁰² -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CY ⁰¹ = CY ⁰² - or -C≡C-, preferably from 1 to 9, 2 to 5 n-alkyl or n-alkoxy, alkenyl, alkenyloxy or alkoxyalkyl having 2 to 9, preferably 2 to 5, carbon atoms, or halogenated alkyl, preferably halogenated alkyl having up to 9 carbon atoms, Alkyl, alkenyl or alkoxy of up to 9 carbon atoms, mono-, di- or oligo- N-alkyl, n-alkoxy, alkenyl, alkenyloxy or alkoxyalkyl, most preferably n-alkyl or alkenyl having up to 9 carbon atoms,

X ¹ is F, Cl, CF ₃ or OCF ₃ , preferably F,

L ¹¹ and L ¹² independently of one another are H or F, preferably at least one of them, more preferably one of them is F,

n is 0 or 1,

Y ⁰¹ and Y ⁰² are independently of each other F, Cl or CN, alternatively one of them may be H,

R ⁰¹ and R ⁰² are, independently of each other, H or alkyl having 1 to 12 carbon atoms.

- at least one compound of formula II:

In this formula,

R ²¹ and R ²² are independently of each other preferably straight or branched chain alkyl of 1 to 20 carbon atoms which is unsubstituted or mono- or poly-substituted with F, Cl or CN, preferably F, with at least one CH ₂ groups are in each case independently of one another, -O-, -S-, -NR ^01- , -SiR ⁰¹ R ⁰² -, -CO-, - COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CY ⁰¹ = CY ⁰² - or -C≡C-, Alkenyl, alkenyloxy or alkoxyalkyl having 2 to 9, preferably 2 to 5, carbon atoms, or preferably n-alkyl or alkoxyalkyl having 1 to 9, preferably 2 to 5, carbon atoms or n-alkoxy, Halogenated alkyl, halogenated alkenyl or halogenated alkoxy, preferably monofluorinated, di- or oligofluorinated alkyl, alkenes having up to 9 carbon atoms Or alkoxy, most preferably 9 or less carbon atoms in the alkyl n-, n- alkoxy, alkenyl, alkenyl and yloxy or alkoxyalkyl, and most preferably

R < ²¹ > is n-alkyl or alkenyl, preferably n-alkyl,

R < ²² > is n-alkyl or alkenyl,

m is 0 or 1,

L < ² > is H or F, preferably F,

Y ⁰¹ , Y ⁰² , R ⁰¹ and R ⁰² have the respective meanings given in the above formula (I).

Optionally, preferably, at least one compound selected from the group of the following formulas III and IV:

In this formula,

R ³¹ , R ³² , R ⁴¹ and R ⁴² independently of one another are each preferably straight or branched chain alkyl having 1 to 20 carbon atoms which is unsubstituted or mono- or poly-substituted with F, Cl or CN, Wherein one or more CH ₂ groups are in each case independently of one another selected from the group consisting of -O-, -S-, -NR ⁰¹ -, -SiR ⁰¹ R ⁰² - , -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CY ⁰¹ = CY ^02- or -C≡C-, Preferably n-alkyl or n-alkoxy of 1 to 9 carbon atoms, preferably 2 to 5 carbon atoms, alkenyl, alkenyloxy or alkoxyalkyl of 2 to 9 carbon atoms, preferably 2 to 5 carbon atoms, Halogenated alkyl, halogenated alkenyl or halogenated alkoxy having up to 9 carbon atoms, preferably monovalent, perfluorinated or oligofluorinated Kiel, alkenyl or alkoxy, most preferably 9 or less carbon atoms in the alkyl n-, n- alkoxy, alkenyl, alkenyl and yloxy or alkoxyalkyl, and most preferably

R < ³¹ > is n-alkyl or alkenyl,

R ³² is n-alkyl, alkenyl, n-alkoxy or alkenyloxy,

내지

는, 서로 독립적으로

To

Independently of one another,

이고,

ego,

p is 0, 1 or 2, preferably 0 or 1, most preferably 0,

Y ⁰¹ , Y ⁰² , R ⁰¹ and R ⁰² have the respective meanings given in the above formula (I).

The mesogenic medium according to the present invention is a compound selected from the group of compounds of the formula I, preferably those of the formulas I-1 to I-3, preferably selected from the following formulas I-1 and I-2 , More preferably one or more compounds each of the following general formulas (I-1) and (1-2):

In this formula,

The variables have the respective meanings given in the above formula (I), preferably

R < ^{1 >} is n-alkyl or alkenyl, most preferably n-alkyl,

X ¹ is F, Cl or CF ₃ , most preferably F.

The mesogenic medium according to the present invention is a compound selected from the group of compounds of formula II, preferably compounds of the following formulas II-1 to II-3, preferably selected from the following formulas II-1 and II-3 , More preferably at least one compound each of the following general formulas (II-1) and (II-3):

In this formula,

The variables have the respective meanings given in the above formula (II), preferably

R ²¹ is n-alkyl or alkenyl, most preferably n-alkyl,

R ²² is n-alkyl or alkenyl, most preferably n-alkyl.

Also, in a particularly preferred embodiment, the mesogenic medium according to the present invention comprises

R ²¹ is an alkyl, preferably n- alkyl, most preferably ethyl or propyl, R ²² is alkyl, preferably n- alkyl, most preferably ethyl, propyl, butyl or pentyl is of formula II-1 One or more compounds, and / or

R ²¹ is alkyl, preferably n-alkyl, most preferably ethyl or propyl, and R ²² is alkenyl, preferably [-CH ₂ ] ₂ -CH = CH ₂ or [-CH ₂ ] ₂ -CH = C-CH ₃ one or more compounds of formula II-1, and / or

Compounds of formula II-3 wherein R ²¹ is alkyl, preferably n-alkyl, most preferably propyl, butyl, pentyl and R ²² is alkyl, preferably n-alkyl, most preferably ethyl or propyl, One or more.

Preferably, the mesogenic medium according to the invention is a compound selected from the group of compounds of formula III, preferably compounds of formula III-1 and III-2, preferably compounds of formula III-2: Includes:

In the above equation, the variables have the respective meanings given above, and preferably

R ³¹ is a non-fluorinated alkyl or non-fluorinated alkoxy of 1 to 15 carbon atoms, or a non-fluorinated alkenyl of 2 to 15 carbon atoms, a non-fluorinated alkenyloxy or a non-fluorinated alkoxyalkyl , Preferably alkyl, particularly preferably n-alkyl,

R ³² represents H, a non-fluorinated alkyl or non-fluorinated alkoxy of 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, particularly preferably 3 carbon atoms,

R ³¹ represents C _n H _{2n + 1} or CH ₂ = CH- (CH ₂ ) _z ,

R ³² represents C _m H _{2m +1} , OC _m H _{2m +1} or (CH ₂ ) _z -CH = CH ₂ ,

n and m each independently represent an integer ranging from 0 to 15, preferably from 1 to 7, particularly preferably from 1 to 5,

z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R ³¹ and R ³² ) herein are (C _n H _{2n +1} and C _m H _{2m +1} ) and (C _n H _{2n +1} and OC _m H _{2m +1} ) in particular.

Preferably, the mesogenic medium according to the invention is a compound selected from the group of compounds of formula III-1, preferably compounds of formula III-1a to III-1c, preferably compounds of formula III- / RTI > and / or < RTI ID = 0.0 > III-1c, <

In the above equation, the variables have the respective meanings given above.

Preferably the mesogenic medium according to the invention is a compound selected from the group of compounds of formula III-2, preferably compounds of formula III-2a to III-2d, preferably compounds of formula III-2a, III-2b and III-2d, most preferably a compound of formula III-2a: < EMI ID =

In the above equation, the variables have the respective meanings given above, and preferably

R ³¹ is a non-fluorinated alkyl or non-fluorinated alkoxy of 1 to 15 carbon atoms, or a non-fluorinated alkenyl of 2 to 15 carbon atoms, a non-fluorinated alkenyloxy or a non-fluorinated alkoxyalkyl , Preferably alkyl, particularly preferably n-alkyl,

R ³² represents H, a non-fluorinated alkyl or non-fluorinated alkoxy of 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, particularly preferably 3 carbon atoms,

R ³¹ represents C _n H _{2n + 1} or CH ₂ = CH- (CH ₂ ) _z ,

R ³² represents C _m H _{2m +1} or OC _m H _{2m +1} or (CH ₂ ) _z -CH = CH ₂ ,

n and m each independently represent an integer ranging from 0 to 15, preferably from 1 to 7, particularly preferably from 1 to 5,

z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R ³¹ and R ³² ) herein are (C _n H _{2n +1} and C _m H _{2m +1} ) and (C _n H _{2n +1} and OC _m H _{2m +1} ) in particular.

In a preferred embodiment of the present invention, the liquid crystal medium comprises at least one compound of formula IV,

R ⁴¹ is n-alkyl or alkenyl, more preferably n-alkyl, most preferably C _n H _{2n + 1} ,

R ⁴² is alkenyl, more preferably CH ₂ ═CH- [CH ₂ -] _z or CH ₃ -CH ₂ ═CH- [CH ₂ ] _z , [-CH ₂ ] ₂ -CH═CH ₂ or [ -CH ₂ ] ₂ -CH = C-CH ₃ ,

n is an integer ranging from 0 to 15, preferably from 1 to 7, particularly preferably from 1 to 5,

z is 0, 1, 2, 3 or 4, preferably 0 or 2,

Include compounds of formula (IV).

In a preferred embodiment of the present invention, the liquid crystal medium comprises at least one compound of the formulas I-1 and / or I-2 and / or I-3.

In a preferred embodiment of the present invention, the liquid crystal medium comprises at least one compound of formula II-1 and / or II-2 and / or II-3.

The liquid crystal medium according to the invention preferably comprises a compound selected from the group of compounds of formulas I, II, III and optionally IV, preferably compounds of formula I, II, III and IV, More preferably they consist essentially of these, and very particularly preferably they consist entirely of these.

"Containing ", as used herein with a composition, means that the individual (i. E., Medium or ingredient) contains the indicated component or compound preferably in a total concentration of at least 10%, more preferably at least 20% .

In this context, "predominantly consisting of" means that the individual comprises at least 55%, preferably at least 60%, more preferably at least 70% of the indicated component or compound.

In this context, "essentially consisting of" means that the individual comprises at least 80%, preferably at least 90%, more preferably at least 95% of the indicated component or compound.

In this connection, "complete with" means that the individual preferably comprises at least 98%, more preferably at least 99, even more preferably at least 100.0% of the indicated components or compounds .

Other mesogenic compounds not specifically mentioned above may also be used arbitrarily and advantageously in the medium according to the invention. Such compounds are known to those skilled in the art.

The liquid crystal medium according to the present invention preferably has a clearing point of 90 DEG C or higher, more preferably 100 DEG C or higher, still more preferably 120 DEG C or higher, particularly preferably 150 DEG C or higher, very particularly preferably 170 DEG C or higher .

The nematic phase of the medium according to the invention preferably extends to a low temperature of at least 20 ° C, more preferably not more than 0 ° C, still more preferably not more than -10 ° C, most preferably not more than -20 ° C. At the same time, it is preferably extended to a temperature of at least 90 ° C, preferably at least 95 ° C, more preferably at least 100 ° C, in particular at least 110 ° C.

At 1 kHz and 20 캜, Δε of the liquid crystal medium according to the present invention is preferably at least 1, more preferably at least 2, very preferably at least 3, preferably at the same time, 10 or less, more preferably 9 or less, More preferably 8 or less, and most preferably even 6 or less.

The Δn of the liquid crystal medium according to the present invention at 589.3 nm (Na ^D ) and 20 ° C. is preferably in the range of 0.160 to 0.400, more preferably in the range of 0.180 to 0.300, still more preferably in the range of 0.190 to 0.250 , Very particularly preferably in the range of 0.195 to 0.220.

According to the present invention, the compound of formula I is preferably present in an amount of from 5% to 35%, more preferably from 10% to 25%, even more preferably from 12% to 22%, most preferably from 15% % ≪ / RTI > to < RTI ID = 0.0 > 19% < / RTI >

According to the present invention, the compound of formula (II) is preferably present in an amount of 10 to 100%, more preferably 35 to 55%, still more preferably 40 to 50%, most preferably 42 % ≪ / RTI > to < RTI ID = 0.0 > 49% < / RTI >

According to the present invention, the compound of formula III is preferably used in an amount of 5% to 50%, more preferably 10% to 30%, still more preferably 15% to 25%, very preferably 18% to 22% % ≪ / RTI > in the liquid crystal medium.

According to the present invention, the compound of formula (IV) is preferably used in an amount of 5% to 30%, more preferably 7% to 25%, still more preferably 10% to 20%, very preferably 11% % ≪ / RTI > in the liquid crystal medium.

The liquid crystal medium preferably contains a total of 70% to 100%, more preferably 80% to 100%, very preferably 90% to 100%, especially 95% to 100% IV, preferably compounds of formula (I), (II), (III) and (IV), more preferably consist predominantly of these, and very preferably completely

In a preferred embodiment of the present invention, the liquid crystal medium comprises:

One or more compounds of the formula PUQU-3-F and / or PGUQU-3-F and / or

One or more compounds of the formula PGP-2-3 and / or PGP-2-4 and / or PGP-2-5 and / or

One or more compounds of the formula PGP-1-2V and / or PGP-2-2V and / or PGP-3-2V and / or PGP-2-2V1 and / or

One or more compounds of the formula CPGP-4-3 and / or CPGP-5-2 and / or CPGP-5-3 and / or

One or more compounds of the formula CC-3-V and / or CC-3-V1 and / or

At least one compound of the formula CP-3-1 and / or CP-3-2 and / or CP-3-O1 and / or CP-3-O2 and /

At least one compound of the formula PP-1-2V and / or PP-1-2V1.

Each abbreviation is generated according to the following Tables A to C and is described in Table D below.

The expression " having a positive permittivity "is used herein to describe a compound or component with Δ∈> 3.0, and the expression" with a neutral permittivity "is intended to describe a compound or component with -1.5 ≦ Δε ≦ 3.0 , The expression "having a negative dielectric constant" is to describe a compound or component with Δ∈ <-1.5. ? Is determined at a frequency of 1 kHz and at 20 占 폚. The dielectric anisotropy of each compound is determined from the result of a 10% solution of each individual compound in the nematic host mixture. If the solubility of each compound in the host mixture is less than 10%, the concentration is reduced to 5%. The capacity of the test mixture is determined in both a cell with a homeotropic orientation and a cell with a homogeneous orientation. The cell thickness in both types of cells is about 20 탆. The applied voltage is a rectangular wave with a frequency of 1 kHz and typically an effective value of 0.5 to 1.0 V, but this is always chosen to be below the threshold of the capacitance of the respective test mixture.

The following definitions apply here.

Δε ≡ (ε _∥ - ε _⊥ )

ε _average ≡ (ε _∥ + 2ε _⊥ ) / 3

The host mixture used for the compound having a positive dielectric constant is the mixture ZLI-4792, the host mixture used for the compound having the neutral permittivity and the compound having the negative dielectric constant is the mixture ZLI-3086, 0.0 &gt; (Merck KGaA). &Lt; / RTI &gt; The absolute value of the dielectric constant of these compounds is determined from the change in the respective value of the host mixture when the compound of interest is added. The value is extrapolated to a 100% concentration of the compound of interest.

A compound having a nematic phase at a measurement temperature of 20 占 폚 is measured by itself. Others are treated like compounds.

In all cases, unless expressly stated otherwise, the expression "threshold voltage" herein refers to the optical threshold and is presented as 10% relative contrast (V ₁₀ ) V ₅₀ ), and the expression "saturation voltage" refers to optical saturation and is presented as 90% relative contrast (V ₉₀ ). All characteristic voltages are determined under vertical observation. Freedericks - The threshold voltage (V ₀ ) of capacitance, also referred to as threshold (VF _r ), is only used when explicitly mentioned.

Unless expressly stated otherwise, the ranges of parameters set forth herein all include limits.

Additional preferred ranges occur when different upper and lower limits indicating various ranges of properties are combined with each other.

Unless expressly stated otherwise, the following conditions and definitions apply throughout this application. All concentrations are given in weight percent, with respect to each whole mixture, all temperatures are given in degrees centigrade, and all temperature differences are given in degrees Celsius. All physical properties are described in Merck Liquid Crystals, Physical Properties of Liquid Crystals, Status Nov. 1997, Merck KGaA, Germany] and is presented for a temperature of 20 ° C. The optical anisotropy (? N) is determined at a wavelength of 589.3 nm. The dielectric anisotropy (DELTA epsilon) is determined at a frequency of 1 kHz. All other electro-optical properties as well as the threshold voltage were determined using a test cell manufactured in Merck KGaA, Germany. The test cell for determining [Delta] [mu] has a cell thickness of about 20 [mu] m. The electrode was a circular ITO electrode with an area of 1.13 cm 2 and a guard ring. The orientation layer was SE-1211 from Nissan Chemicals in the case of vertical orientation (ε _⊥ ) and polyimide AL-1054 from Synthetic Rubber in the case of horizontal orientation (∈ _∥ ) . The capacitance was determined with a frequency response analyzer Solatron 1260 using a sine wave with a voltage of 0.3 V _rms .

The light used for electro-optical measurements was white light. We have set up here using a DMS instrument available from Autronic-Melchers, Germany. The characteristic voltage was determined under vertical observation. The threshold voltage V ₁₀ , the mid-gray voltage V ₅₀ and the saturation voltage V ₉₀ were determined for 10%, 50% and 90% relative contrast, respectively.

The term "compound" herein, unless otherwise stated, means both a compound and a plurality of compounds.

The liquid crystal medium according to the invention preferably has a nematic phase of at least -20 캜 to 80 캜, preferably -30 캜 to 85 캜, particularly preferably -40 캜 to 100 캜, in each case. The expression "having a nematic phase" herein means that no smectic phase and crystallization are observed on the one hand at low temperatures of the corresponding temperature and on the other hand a clearing from the nematic phase upon heating It means that it does not happen. Investigation at low temperature is carried out in a flow viscometer at the corresponding temperature and checked by storing in a test cell having a layer thickness of 5 [mu] m for at least 100 hours. At high temperature, the longevity point is measured in the capillary by a conventional method.

(N, I) of the liquid crystal medium is preferably 80 DEG C or more, more preferably 85 DEG C or more, still more preferably 90 DEG C or more, and most preferably 95 DEG C or more, Is preferably 130 ° C or lower, more preferably 120 ° C or lower, still more preferably 110 ° C or lower, and most preferably 100 ° C or lower.

In a preferred embodiment of the present invention, the liquid crystal medium has a positive dielectric anisotropy (DELTA epsilon) at a low operating frequency. The dielectric anisotropy is preferably at least 1.5, more preferably at least 2.0, still more preferably at least 2.5, most preferably at least 3.0, preferably at most 15.0, even more preferably at most 10.0, Is 8.0 or less, and most preferably 6.0 or less.

Further, the liquid crystal medium according to the present invention is characterized by a relatively high optical anisotropy, that is, a birefringence value? N. Such a birefringence value is preferably 0.170 or more, more preferably 0.180 or more, still more preferably 0.190 or more, most preferably 0.200 or more, still more preferably 0.350 or less, still more preferably 0.300 or less Is 0.270 or less, and most preferably 0.250 or less.

The liquid crystal medium according to the invention is also characterized by a suitable rotational viscosity (gamma ₁ ). The rotational viscosity is preferably 250 mPa · s or less, more preferably 200 mPa · s or less, still more preferably 150 mPa · s or less, and most preferably 130 mPa · s or more. Preferably, the rotational viscosity of the medium is as low as possible. However, the practical minimum possible is 80 mPa · s or more, or even 100 mPa · s or more.

In the corresponding geometry, preferred liquid crystal materials have excellent properties, especially for 3D lenses of the EIB type.

The term "alkyl" preferably refers to straight and branched chain alkyl groups of 1 to 15 carbon atoms, as well as cycloalkyl groups, especially straight chain methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl, as well as cyclopropyl and cyclohexyl . Groups having 2 to 10 carbon atoms are generally preferred.

The term "alkenyl " includes straight and branched chain alkenyl groups of 2 to 15 carbon atoms, especially straight chain groups. Particularly preferred alkenyl groups are C ₂ -C ₇ -1E-alkenyl, C ₄ -C ₇ -3 E -alkenyl, C ₅ -C ₇ -4 alkenyl, C ₆ -C ₇ -5 -alkenyl and C ₇ -alkenyl, in particular C ₂ -C ₇ -1E-alkenyl, C ₄ -C ₇ -3 E-alkenyl and C ₅ -C ₇ -4 -alkenyl. Examples of other preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E- 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl and 6-heptenyl. Groups having up to 5 carbon atoms are generally preferred.

The term "fluoroalkyl" preferably refers to straight chain groups having terminal fluorine atoms, such as fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4- fluorobutyl, 6-fluorohexyl and 7-fluoroheptyl. However, other positions of fluorine are not excluded.

The term "oxaalkyl" or "alkoxyalkyl" preferably includes a straight-chain radical of the formula C _n H _{2n + 1} -O- (CH ₂ ) _m , wherein n and m, Represents an integer of 1 to 10. Preferably, n is 1 and m is 1 to 6.

A compound containing a vinyl end group and a compound containing a methyl end group have a low rotational viscosity.

The liquid crystal medium according to the present invention may contain additional additives and chiral dopants in conventional concentrations. The total concentration of these additional components ranges from 0% to 10%, preferably from 0.1% to 6%, based on the total mixture. The concentrations of the individual compounds used are preferably in the range of 0.1% to 3%. When referring to the liquid crystal component of the liquid crystal medium and the value and concentration range of the liquid crystal compound in the present application, the concentrations of the components and similar additives are not considered.

The liquid crystal medium according to the present invention is composed of a plurality of compounds, preferably 3 to 30, more preferably 4 to 20, and very preferably 4 to 15 compounds. These compounds are mixed in a conventional manner. Generally, a lesser amount of the compound is dissolved in the compound to be used in a larger amount. It is particularly easy to observe that the dissolution process is completed when the temperature is higher than the clearing point of the compound used at a higher concentration. However, the so-called "multi-container" system, which is a mixture using other so-called pre-mixes, which can be a homogeneous or eutectic mixture of compounds, a multi-bottle system may be used to produce the medium.

The transition T (S, N) from the melting point T (C, N) or T (C, S), the smectic phase (S) to the nematic phase (N) (N, I) is presented in degrees Celsius. All temperature differences are presented in degrees Celsius.

In the present application and particularly in the following examples, the structure of the mesogenic compound is presented as an abbreviation also referred to as acronym. In these acronyms, the formula is abbreviated using the following Tables A to C as follows. The groups C _n H _{2n + 1} , C _m H _{2m + 1} and C ₁ H _{2l + 1} or C _n H _2n-1 , C _m H _2m-1 and C ₁ H _2l- alkenyl, preferably 1 E -alkenyl, wherein n, m and l are each, independently of one another, from 1 to 9, preferably from 1 to 7, or from 2 to 9, Represents an integer of 2 to 7. C _o H _{2o + 1} represents straight-chain alkyl having 1 to 7 carbon atoms, preferably 1 to 4 carbon atoms, or branched alkyl having 1 to 7 carbon atoms, preferably 1 to 4 carbon atoms.

Table A lists the codes used in the ring element of the core structure of the above compounds, and Table B below shows the linking groups. Table C below gives the meaning of the codes for the left and right end groups. Table D below shows the exemplary structures of the compounds with respective abbreviations.

Table A: Ring elements

Table B: Connectors

Table C:

Where n and m are each an integer and the three dots "... " are place-holders for other abbreviations from this table.

The following table, together with the respective abbreviations, represents an exemplary structure. This is presented to illustrate the meaning of the rules for abbreviations. It also suggests compounds that are preferably used.

Table D: Example structure

An exemplary structure of a compound which is particularly preferably used is presented.

Examples of compounds of formula (I) are as follows.

Examples of the compound of the formula (II) are as follows.

Examples of the compound of the formula (III) are as follows.

Examples of the compound of the formula (IV) are as follows.

Examples of further preferred compounds are as follows.

2, 3; 4; 5; 6; 7}, and k {1; 2; 3} ; 4}, preferably 2 or 4, most preferably 2, and 1 {; 1; 2; 3}, preferably 1.

Table E below illustrates exemplary compounds that can be used as stabilizers in the mesogenic medium according to the present invention. The total concentration of these compounds and similar compounds in the medium is preferably 5% or less.

Table E

(Preferably)

In a preferred embodiment of the present invention, the mesogenic medium comprises at least one compound selected from the group of compounds of Table E above.

The mesogenic medium according to the present invention preferably comprises two or more, preferably four or more, compounds selected from the group consisting of the compounds from the above Tables.

The liquid crystal medium according to the present invention contains at least 7, preferably at least 8, compounds selected from the group of the compounds of Table D, preferably at least 3, preferably at least 4 different compounds of the formula do.

[Example]

The following examples illustrate the invention, but are not intended to limit the invention in any way. It will be apparent, however, to those skilled in the art, which properties can be achieved and modified to some extent from physical properties. Thus, combinations of various properties that can be particularly advantageously achieved are well-defined by those skilled in the art.

Example  One

A liquid crystal mixture M-1 having the compositions and characteristics shown in the following table was prepared.

This mixture is particularly well suited for 3D lenses of the EIB type.

Table 3: 60 Hz  And 20 ° C and 60 ° C In each Example  1 voltage holding ratio

Example  2

A liquid crystal mixture M-2 having the compositions and characteristics shown in the following table was prepared.

This mixture is particularly well suited for 3D lenses of the EIB type.

Example  3

A liquid crystal mixture M-3 having the compositions and characteristics shown in the following table was prepared.

This mixture is particularly well suited for 3D lenses of the EIB type.

Example  4

A liquid crystal mixture M-4 having the compositions and characteristics shown in the following table was prepared.

This mixture is particularly well suited for 3D lenses of the EIB type.

Example  5

A liquid crystal mixture M-5 having the compositions and characteristics shown in the following table was prepared.

This mixture is particularly well suited for 3D lenses of the EIB type. However, it was characterized by a lower voltage holding ratio under load, but had a relatively low rotational viscosity.

Example  6

A liquid crystal mixture M-6 having the compositions and characteristics shown in the following table was prepared.

This mixture is particularly well suited for 3D lenses of the EIB type. This was characterized by a low threshold voltage and an excellent voltage holding ratio under load, and had a relatively low rotational viscosity.

Claims (11)

Claims 1. A liquid crystal medium characterized in that it comprises at least one compound of formula (I), at least one compound of formula (II), and optionally at least one compound selected from the group of formula (III)

In the formula (I)
R ¹ is unsubstituted or substituted by F, Cl or CN by mono- or multi-substituted straight or branched chain alkyl, wherein one or more CH ₂ groups, in each case, independently of one another, O, and / or to direct each S atom -O-, -S-, -NR ⁰¹ -, -SiR ⁰¹ R ⁰² -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, - CO-S-, -CY &lt; ¹ &gt; = CY &lt; ⁰² &
X ¹ is F, Cl, CF ₃ or OCF ₃ ,
L ¹¹ and L ¹² are independently of each other H or F,
n is 0 or 1,
Y ⁰¹ and Y ⁰² are independently of each other F, Cl or CN, alternatively one of them may be H,
R ⁰¹ and R ⁰² are, independently of each other, H or alkyl having 1 to 12 carbon atoms,
In the above formula (II)
R ²¹ and R ²² are independently of each other a straight chain or branched chain alkyl which is unsubstituted or monosubstituted or polysubstituted by F, Cl or CN, wherein one or more CH ₂ groups are in each case independently of one another O and / -S-, -NR ^01- , -SiR ⁰¹ R ⁰² -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CY ⁰¹ = CY ⁰² - or -C? C -
m is 0 or 1,
L &lt; ² &gt; is H or F,
Y ⁰¹ , Y ⁰² , R ⁰¹ and R ⁰² have the respective meanings given in the above formula (I)
In Formulas III and IV above,
R ³¹ , R ³² , R ⁴¹ and R ⁴² are independently of each other a straight chain or branched chain alkyl which is unsubstituted or mono- or multiply substituted by F, Cl or CN, in which case at least one CH ₂ group, Independently of one another, -O-, -S-, -NR ⁰¹ -, -SiR ⁰¹ R ⁰² -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -CY ⁰¹ = CY ^02- or -C? C-,
R &lt; ³¹ &gt; is n-alkyl or alkenyl,
R ³² is n-alkyl, alkenyl, n-alkoxy or alkenyloxy,

To

Independently of one another,

ego,
p is 0, 1 or 2, preferably 0 or 1, most preferably 0,
Y ⁰¹ , Y ⁰² , R ⁰¹ and R ⁰² have the respective meanings given in the above formula (I). The method according to claim 1,
RTI ID = 0.0 &gt; (III) &lt; / RTI &gt; 3. The method according to claim 1 or 2,
A liquid crystal medium characterized by comprising at least one compound of formula (IV) as set forth in claim 1. 4. The method according to any one of claims 1 to 3,
Wherein R ²¹ is n-alkyl, R ²² is alkenyl, L ² is F, and m is 1. 5. The method according to any one of claims 1 to 4,
A liquid crystal medium characterized by comprising at least one compound selected from the group of compounds represented by the following formulas (III-1) and (III-2):

In the above equations, the variables all have the respective meanings given in the first paragraph. 6. The method according to any one of claims 1 to 5,
And a birefringence (? N) in the range of 0.15 to 0.40 at 20 占 폚 and 589.3 nm. At least one compound of formula I, at least one compound of formula II and optionally at least one compound of formula III and / or IV, as defined in claim 1, with at least one additional compound and / The method of manufacturing a liquid crystal medium according to any one of claims 1 to 6, Use of a liquid crystal medium according to any one of claims 1 to 6 in a 3D lens. A 3D lens characterized by containing a liquid crystal medium according to any one of claims 1 to 6. A liquid crystal display comprising at least one 3D lens according to claim 9. A method of operating a 3D liquid crystal display by addressing at least one 3D lens according to claim 9.