Patent Application
20230183571
The present invention relates to an LC medium comprising two or more polymerizable compounds, at least one of which contains a substituent comprising a tertiary OH group, to its use for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the PSA (polymer sustained alignment) or SA (self-aligning) mode, to an LC display of the PSA or SA mode comprising the LC medium, and to a process of manufacturing the LC display using the LC medium, especially an energy-saving LC display and energy-saving LC display production process.
The popularity of 8 K and gaming monitors leads to an increased need for LC display (LCD) panels having higher refresh rates and thus for LC media having faster response times. Many of these LCD panels are using polymer stabilized (PS) or polymer sustained alignment modes (PSA) modes, like the PS-VA (vertically aligned), PS-IPS (in-plane switching) or PS-FFS (fringe-field switching) mode or modes derived therefrom, or self-aligned (SA) modes like SA-VA which are polymer stabilized.
In the PS or PSA mode a small amount, typically from 0.1 to 1 % of one or more polymerizable mesogenic compounds, also known as RMs (reactive mesogens), is added to the LC medium. After filling the LC medium into the display the RMs are then polymerized in situ by UV photopolymerization, while a voltage is applied to the electrodes of the display. Thereby a small tilt angle is generated in the LC molecules of the LC medium, which is stabilized by the polymerized RMs. The UV polymerization process, also referred to as “PSA process”, is usually carried out in two steps, a first UV exposure step (“UV1 step”), with application of a voltage, to generate the tilt angle, and a second UV exposure step (“UV2 step”), without application of a voltage, to complete polymerization of the RMs.
In the SA-VA mode the alignment layers are omitted in the display. Instead, a small amount, typically 0.1 to 2.5 %, of a self alignment (SA) additive is added to the LC medium, which induces the desired alignment, for example homeotropic or planar alignment, in situ by a self assembling mechanism. The SA additive usually contains an organic, mesogenic core group and attached thereto one or more polar anchor groups, for example hydroxy, carboxy, amino or thiol groups, which are capable of interacting with the substrate surface, causing the additives on the substrate surface to align and induce the desired alignment also in the LC molecules. The SA additive may also contain one or more polymerizable groups that can be polymerized under similar conditions as the RMs used in the PSA process. The LC medium may in addition to the SA additive also contain one or more RMs.
One method to reduce the response times in LC media for the PSA mode is for example by using compounds with an alkenyl group as components of the LC host mixture. However, this may lead to a decrease of the reliability of the mixture when being exposed to the UV light need to polymerize the RMs additives, which is believed to be caused by a reaction of the alkenyl compound with the polyimide of the alignment layer, which is especially problematic when using shorter UV wavelengths of less than 320 nm. Therefore there is a tendency to use longer UV wavelengths for the PSA process.
UV-LED lamps have also been proposed for use in the PSA process, as they show less energy consumption, longer lifetime and more effective optical energy transfer to the LC medium due to the narrower emission peak, which allows to reduce the UV intensity and/or UV irradiation time. This enables a reduced tact time and savings in energy and production costs. The UV lamps currently available have higher wavelength emission, for example at 365 nm.
Therefore, there is a need for polymerizable LC media which contain RMs that can be effectively polymerized at longer UV wavelengths.
In addition, there is a great demand for PSA or SA displays, and LC media and polymerizable compounds for use in such PSA or SA displays, which enable a high specific resistance at the same time as a large working-temperature range, short response times, even at low temperatures, and a low threshold voltage, a low tilt angle, a high tilt stability, a multiplicity of grey shades, high contrast and a broad viewing angle, have high reliability and high values for the VHR after UV exposure, and, in case of the polymerizable compounds, have low melting points and a high solubility in the LC host mixtures. In displays for mobile applications, it is especially desired to have available LC media that show low threshold voltage and high birefringence.
The present invention is based on the object of providing novel suitable materials, in particular RMs and LC media comprising the same, for use in PSA or SA displays, which do not have the disadvantages indicated above or do so to a reduced extent.
In particular, the invention is based on the object of LC media comprising RMs for use in PSA or SA displays, which enable very high specific resistance values, high VHR values, high reliability, low threshold voltages, short response times, high birefringence, show good UV absorption especially at longer UV wavelengths, preferably in the range from 340 to 380 nm, enable quick and complete polymerization of the RMs, allow the generation of a low tilt angle, preferably as quickly as possible, enable a high stability of the tilt angle even after longer time and/or after UV exposure, reduce or prevent the occurrence of “image sticking” and “ODF mura” in the display, and in case of the RMs polymerize as rapidly and completely as possible and show a high solubility in the LC media which are typically used as host mixtures in PSA or SA displays.
A further object of the invention is to provide LC media for use in PSA displays wherein the RMs exhibit both fast polymerization speed and good reliability parameters, like high VHR or good tilt stability.
A further object of the invention is the provision of novel LC media containing RMs, in particular for optical, electro-optical and electronic applications, and of suitable processes and intermediates for the preparation thereof.
A further object of the invention is to provide LC media containing RMs which show one or more of the following advantageous effects:
It was found that one or more of these objects could be achieved by providing LC media comprising polymerizable compounds as disclosed and claimed hereinafter.
The invention relates to an LC medium comprising one or more polymerizable compounds selected from formula IA and one or more polymerizable compounds selected from formulae IB and IC
wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings
The invention further relates to an LC medium having negative dielectric anisotropy and comprising one or more polymerizable compounds selected from formula IA, one or more polymerizable compounds selected from formulae IB and IC, and further comprising one or more compounds of formula II
wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings
R1 and R2 straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH2-groups are each optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, CR0═CR00—, —C═C—,
in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by F or Cl, R1 and R2 are preferably alkyl or alkoxy having 1 to 6 C atoms,
R0 and R00 H or alkyl with 1 to 12 C atoms, preferably H,
The invention further relates to the use of the LC medium as described above and below in LC displays of the PSA or SA mode.
The invention furthermore relates to a process for preparing an LC medium as described above and below, comprising the steps of mixing one or more polymerizable compounds of formula IA with one or more polymerizable compounds selected from formulae IB and IC, and optionallyone or more compounds of formula II, and optionally with further LC compounds and/or additives.
The invention furthermore relates to an LC display comprising an LC medium according to the invention as described above and below, which is a PSA or SA display, preferably a PS-VA, PS-IPS, PS-FFS or SA-VA display.
The invention furthermore relates to an LC display comprising an LC medium as described above and below wherein the polymerizable compounds are present in polymerized form, which is preferably a PSA or SA display, very preferably a PS-VA, PS-IPS, PS-FFS or SA-VA display.
The invention furthermore relates to an LC display of the PSA type comprising two substrates, at least one which is transparent to light, an electrode provided on each substrate or two electrodes provided on only one of the substrates, and located between the substrates a layer of an LC medium as described above and below, wherein the polymerizable compounds are polymerized between the substrates of the display by UV photopolymerization.
The invention furthermore relates to a process for manufacturing an LC display as described above and below, comprising the steps of filling or otherwise providing an LC medium as described above and below between the substrates of the display, and polymerizing the polymerizable compounds, preferably by irradiation with UV light, preferably having a wavelength >340 nm, preferably >360 nm, preferably in the range from 340 to 400 nm, more preferably in the range from 350 to 390 nm, very preferably in the range from 360 to 380 nm, most preferably in the range from 360 to 368 nm, and preferably while a voltage is applied to the electrodes of the display.
The invention furthermore relates to a process for manufacturing an LC display as described above and below, wherein irradiation of the polymerizable compounds is carried out using a UV-LED lamp.
The LC media according to the present invention show the following advantageous properties when used in PSA displays:
In addition the LC media according to the present invention show one or more of the following advantageous properties:
An alkenyl group in the compounds of formula II or other components of the LC medium as disclosed below is not considered to be within the meaning of the term “polymerizable group” as used herein. The conditions for the polymerization of the polymerizable compounds of the LC medium are preferably selected such that alkenyl substituents do not participate in the polymerization reaction. Preferably the LC media disclosed and claimed in the present application do not contain an additive that initiates or enhances the participation of the alkenyl group in a polymerization reaction.
Unless stated otherwise, the polymerizable compounds and the compounds of formula II are preferably selected from achiral compounds.
As used herein, the expression “UV light having a wavelength of” followed by a given range of wavelengths (in nm), or by a given lower or upper wavelength limit (in nm), means that the UV emission spectrum of the respective radiation source has an emission peak, which is preferably the highest peak in the respective spectrum, in the given wavelength range or above the given lower wavelength limit or below the given upper wavelength limit and/or that the UV absorption spectrum of the respective chemical compound has a long or short wavelength tail that extends into the given wavelength range or above the given lower wavelength limit or below the given upper wavelength limit.
As used herein, the term “full width half maximum” or “FWHM” means the width of a spectrum curve measured between those points on the y-axis which are half the maximum amplitude.
As used herein, the term “substantially transmissive” means that the filter transmits a substantial part, preferably at least 50% of the intensity, of incident light of the desired wavelength(s). As used herein, the term “substantially blocking” means that the filter does not transmit a substantial part, preferably at least 50% of the intensity, of incident light of the undesired wavelengths. As used herein, the term “desired (undesired) wavelength” e.g. in case of a band pass filter means the wavelengths inside (outside) the given range of λ, and in case of a cut-off filter means the wavelengths above (below) the given value of λ.
As used herein, the terms “active layer” and “switchable layer” mean a layer in an electrooptical display, for example an LC display, that comprises one or more molecules having structural and optical anisotropy, like for example LC molecules, which change their orientation upon an external stimulus like an electric or magnetic field, resulting in a change of the transmission of the layer for polarized or unpolarized light.
As used herein, the terms “tilt” and “tilt angle” will be understood to mean a tilted alignment of the LC molecules of an LC medium relative to the surfaces of the cell in an LC display (here preferably a PSA display), and will be understood to be inclusive of “pretilt” and “pretilt angle”. The tilt angle here denotes the average angle (< 90°) between the longitudinal molecular axes of the LC molecules (LC director) and the surface of the plane-parallel outer plates which form the LC cell. A low absolute value for the tilt angle (i.e. a large deviation from the 90° angle) corresponds to a large tilt here. A suitable method for measurement of the tilt angle is given in the examples. Unless indicated otherwise, tilt angle values disclosed above and below relate to this measurement method.
As used herein, the terms “reactive mesogen” and “RM” will be understood to mean a compound containing a mesogenic or liquid crystalline skeleton, and one or more functional groups attached thereto which are suitable for polymerization and are also referred to as “polymerizable group” or “P”.
Unless stated otherwise, the term “polymerizable compound” as used herein will be understood to mean a polymerizable monomeric compound.
An SA-VA display according to the present invention will be of the polymer stabilised mode as it contains, or is manufactured by use of, an LC medium containing RMs of formula IA and formula IB and/or formula IC. Consequently as used herein, the term “SA-VA display” when referring to a display according to the present invention will be understood to refer to a polymer stabilised SA-VA display even if not explicitly mentioned.
As used herein, the term “low-molecular-weight compound” will be understood to mean to a compound that is monomeric and/or is not prepared by a polymerization reaction, as opposed to a “polymeric compound” or a “polymer”.
As used herein, the term “unpolymerizable compound” will be understood to mean a compound that does not contain a functional group that is suitable for polymerization under the conditions usually applied for the polymerization of the RMs.
The term “mesogenic group” as used herein is known to the person skilled in the art and described in the literature, and means a group which, due to the anisotropy of its attracting and repelling interactions, essentially contributes to causing a liquid-crystal (LC) phase in low-molecular-weight or polymeric substances. Compounds containing mesogenic groups (mesogenic compounds) do not necessarily have to have an LC phase themselves. It is also possible for mesogenic compounds to exhibit LC phase behaviour only after mixing with other compounds and/or after polymerization. Typical mesogenic groups are, for example, rigid rod- or disc-shaped units. An overview of the terms and definitions used in connection with mesogenic or LC compounds is given in Pure Appl. Chem. 2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.
The term “spacer group”, hereinafter also referred to as “Sp”, as used herein is known to the person skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. As used herein, the terms “spacer group” or “spacer” mean a flexible group, for example an alkylene group, which connects the mesogenic group and the polymerizable group(s) in a polymerizable mesogenic compound.
Above and below,
denotes a trans-1,4-cyclohexylene ring, and
denotes a 1,4-phenylene ring.
In a group
the single bond shown between the two ring atoms can be attached to any free position of the benzene ring.
If in the formulae shown above and below a group R1-13, R41, R42, R51, R52, RQ, R, R2A, R2B, RIIIA, R1N, R2N, RB1, RB2, RCR1, RCR2, or L denotes an alkyl radical and/or an alkoxy radical, this may be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 C atoms and accordingly preferably denotes ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexyloxy or heptyloxy, furthermore methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.
If in the formulae shown above and below a group R1-13, R41, R42, R51, R52, RQ, R, R2A, R2B, RIIIA, R1N, R2N, RB1, RB2, RCR1, RCR2, or L denotes an alkyl radical wherein one or more CH2 groups are each replaced by S, this may be straight-chain or branched. It is preferably straight-chain, has 1, 2, 3, 4, 5, 6 or 7 C atoms and accordingly preferably denotes thiomethyl, thioethyl, thiopropyl, thiobutyl, thiopentyl, thiohexyl or thioheptyl.
Oxaalkyl preferably denotes straight-chain 2-oxapropyl (= methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxa-decyl.
If in the formulae shown above and below a group R1-13, R41, R42, R51, R52, RQ, R, R2A, R2B, RIIIA, R1N, R2N, RB1, RB2, RCR1, RCR2, or L denotes an alkoxy or oxaalkyl group it may also contain one or more additional oxygen atoms, provided that oxygen atoms are not linked directly to one another.
In another preferred embodiment, one or more of R1-13, R41, R42, R51, R52, RQ, R, R2A, R2B, RIIIA, R1N, R2N, RB1, RB2, RCR1, RCR2, or L are selected from the group consisting of
—S1—F, —O—S1—F, —O—S1—O—S2, wherein S1 is C1-12-alkylene or C2-12-alkenylene and S2 is H, C1-12-alkyl or C2-12-alkenyl, and very preferably are selected from the group consisting of
-OCH2OCH3, —O(CH2)2OCH3, —O(CH2)3OCH3, —O(CH2)4OCH3, —O(CH2)2F, —O(CH2)3F, —O(CH2)4F.
If in the formulae shown above and below a group R1-13, R41, R42, R51, R52, RQ, R, R2A, R2B, RIIIA, R1N, R2N, RB1, RB2, RCR1, RCR2, or L denotes an alkyl radical in which one CH2 group has been replaced by —CH═CH—, this may be straight-chain or branched. It is preferably straight-chain and has 2 to 10 C atoms. Accordingly, it denotes, in particular, vinyl, prop-1- or -2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-, -4-, -5- or -6-enyl, oct-1-, -2-, -3-, -4-, -5-, -6- or -7-enyl, non-1-, -2-, -3-, -4-, -5-, -6-, -7- or -8-enyl, dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or -9-enyl.
If in the formulae shown above and below a group R1-13, R41, R42, R51, R52, RQ, R, R2A, R2B, RIIIA, R1N, R2N, RB1, RB2, RCR1, RCR2, or L denotes an alkyl or alkenyl radical which is at least monosubstituted by halogen, this radical is preferably straight-chain, and halogen is preferably F or Cl. In the case of polysubstitution, halogen is preferably F. The resultant radicals also include perfluorinated radicals. In the case of monosubstitution, the fluorine or chlorine substituent may be in any desired position, but is preferably in the co-position.
Halogen is preferably F or Cl, very preferably F.
The group —CR0═CR00— is preferably —CH═CH—. —CO—, —C(═O)— and —C(O)— denote a carbonyl group, i.e.
Preferred substituents L, are, for example, F, Cl, —CN, P—Sp—, or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH2-groups are each optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, or —O—CO—O— in such a manner that O— and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by P, F or Cl.
Particularly preferred substituents L are, for example, F, Cl, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, and OC2F5.
is preferably
in which L has one of the meanings indicated above.
The polymerizable group P is a group which is suitable for a polymerization reaction, such as, for example, free-radical or ionic chain polymerization, polyaddition or polycondensation, or for a polymer-analogous reaction, for example addition or condensation onto a main polymer chain. Particular preference is given to groups for chain polymerization, in particular those containing a C═C double bond or —C≡C— triple bond, and groups which are suitable for polymerization with ring opening, such as, for example, oxetane or epoxide groups.
Preferred groups P are selected from the group consisting of CH2═CW1—CO—O—, CH2═CW1—CO—,
CH2═CW2—(O)k3—, CW1═CH—CO—(O)k3—, CW1═CH—CO—NH—, CH2═CW1—CO—NH—, CH3—CH═CH—O—, (CH2═CH)2CH—OCO—, (CH2═CH—CH2)2CH—OCO—, (CH2═CH)2CH—O—, (CH2═CH—CH2)2N—, (CH2═CH—CH2)2N—CO—, HO—CW2W3—, HS—CW2W3—, HW2N—, HO—CW2W3—NH—, CH2═CW1—CO—NH—, CH2═CH—(COO)k1—Phe—(O)k2—, CH2═CH—(CO)k1—Phe—(O)k2—, Phe—CH═CH—, HOOC—, OCN— and W4W5W6Si—, in which W1 denotes H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W2 and W3 each, independently of one another, denote H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W4, W5 and W6 each, independently of one another, denote CI, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W7 and W8 each, independently of one another, denote H, Cl or alkyl having 1 to 5 C atoms, Phe denotes 1 ,4-phenylene, which is optionally substituted by one or more radicals L as defined above which are other than P—Sp—, k1, k2 and k3 each, independently of one another, denote 0 or 1, k3 preferably denotes 1, and k4 denotes an integer from 1 to 10.
Very preferred groups P are selected from the group consisting of CH2═CW1—CO—O—, CH2═CW1—CO—,
CH2═CW2—O—, CH2═CW2—, CW1═CH—CO—(O)k3—, CW1═CH—CO—NH—, CH2═CW1—CO—NH—, (CH2═CH)2CH—OCO—, (CH2═CH—CH2)2CH—OCO—, (CH2═CH)2CH—O—, (CH2═CH—CH2)2N—, (CH2═CH—CH2)2N—CO—, CH2═CW1—CO—NH—, CH2═CH—(COO)k1,—Phe—(O)k2—, CH2═CH—(CO)k1,—Phe—(O)k2—, Phe—CH═CH— and W4W5W6Si—, in which W1 denotes H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W2 denotes H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W4, W5 and W6 each, independently of one another, denote Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W7 and W8 each, independently of one another, denote H, Cl or alkyl having 1 to 5 C atoms, Phe denotes 1,4-phenylene, k1, k2 and k3 each, independently of one another, denote 0 or 1, k3 preferably denotes 1, and k4 denotes an integer from 1 to 10.
Very particularly preferred groups P are selected from the group consisting of CH2═CW1—CO—O—, in particular CH2═CH—CO—O—, CH2═C(CH3)—CO—O— and CH2═CF—CO—O—, furthermore CH2═CH—O—, (CH2═CH)2CH—O—CO—, (CH2═CH)2CH—O—,
Further preferred polymerizable groups P are selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably from acrylate and methacrylate.
Very preferably all polymerizable groups in the polymerizable compound have the same meaning.
If the spacer group Sp is different from a single bond, it is preferably of the formula Sp″-X″, so that the respective radical P—Sp— conforms to the formula P-Sp″—X″—, wherein
Sp″ denotes linear or branched alkylene having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN and in which, in addition, one or more non-adjacent CH2 groups may each be replaced, independently of one another, by —O—, —S—, —NH—, —N(R0)—, —Si(R0R00)—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —S—CO—, —CO—S—, —N(R00)—CO—O—, —O—CO—N(R0)—, —N(R0)—CO—N(R00)—, —CH═CH— or —C≡C—in such a way that O and/or S atoms are not linked directly to one another,
X″ denotes —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CO—N(R0)—, —N(R0)—CO—, —N(R0)—CO—N(R00)—, —OCH2—, —CH2O—, —SCH2—, —CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —CF2CH2—, —CH2CF2—, —CF2CF2—, —CH═N—, —N═CH—, —N═N—, —CH═CR0—, —CY2═CY3—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH— or a single bond,
R0 and R00 each, independently of one another, denote H or alkyl having 1 to 20 C atoms, and
Y2 and Y3 each, independently of one another, denote H, F, Cl or CN.
X″ is preferably —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR0—, —NR0—CO—, —NR0—CO—NR00— or a single bond.
Typical spacer groups Sp and —Sp″—X″— are, for example, —(CH2)p1—, —(CH2)p1—O—, —(CH2)p1—O—CO—, —(CH2)p1—CO—O-, —(CH2)p1—O—CO—O—, —(CH2CH2O)q1—CH2CH2—, —CH2CH2—S—CH2CH2—, —CH2CH2—NH—CH2CH2— or —(SiR0R00—O)p1—, in which p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R0 and R00 have the meanings indicated above.
Particularly preferred groups Sp and —Sp″—X″— are —(CH2)p1—, —(CH2)p1—O—, -(CH2)p1—O—CO—, —(CH2)p1—CO—O—, —(CH2)p1—O—CO—O—, in which p1 has the meaning indicated above.
Particularly preferred groups Sp″ are, in each case straight-chain, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methylimino-ethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.
In a preferred embodiment of the invention the compounds of formula IA and/or IB and/or IC and their subformulae contain a spacer group Sp that is substituted by one or more polymerizable groups P, so that the group Sp-P corresponds to Sp(P)s, with s being ≥2 (branched polymerizable groups).
Preferred compounds of formula IA, IB and IC according to this preferred embodiment are those wherein s is 2, i.e. compounds which contain a group Sp(P)2. Very preferred compounds of formula IA and IB according to this preferred embodiment contain a group selected from the following formulae:
in which P is as defined in formula I,
alkyl denotes a single bond or straight-chain or branched alkylene having 1 to 12 C atoms which is unsubstituted or mono- or polysubstituted by F, Cl or CN and in which one or more non-adjacent CH2 groups may each, independently of one another, be replaced by —C(R0)═C(R0)—, —C≡C—, —N(R0)—, —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another, where R° denotes H or alkyl having 1 to 20 C atoms,
aa and bb each, independently of one another, denote 0, 1, 2, 3, 4, 5 or 6,
X has one of the meanings indicated for X″, and is preferably O, CO, SO2, O—CO—, CO—O or a single bond.
Preferred spacer groups Sp(P)2 are selected from formulae S1, S2 and S3.
Very peferred spacer groups Sp(P)2 are selected from the following subformulae:
P is preferably selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, very preferably from acrylate and methacrylate, most preferably from methacrylate.
Further preferably all polymerizable groups P that are present in the same compound have the same meaning, and very preferably denote acrylate or methacrylate, most preferably methacrylate.
Sp preferably denotes a single bond or —(CH2)p1—, —(CH2)p2—CH═CH—(CH2)p3—, -O—(CH2)p1—, —O—CO—(CH2)p1—, or —CO—O—(CH2)p1—, wherein p1 is 2, 3, 4, 5 or 6, preferably 2 or 3, p2 and p3 are independently of each other 0, 1, 2 or 3 and, if Sp is —O—(CH2)p1—, —O—CO—(CH2)p1 or —CO—O—(CH2)p1 the O-atom or CO-group, respectively, is linked to a benzene ring of group M1, M2, or M3.
In a preferred embodiment in the compounds of formula IA and/or IB and/or IC at least one group Sp is a single bond.
In a very preferred embodiment in the compounds of formula IB all groups Sp are a single bond.
In another preferred embodiment in the compounds of formula IA and/or IB and/or IC at least one group Sp is a single bond and at least one group Sp is different from a single bond.
If a group Sp is different from a single bond, it is preferably selected from -(CH2)p1—, —(CH2)p2—CH═CH—(CH2)p3—, —O—(CH2)p1—, —O—CO—(CH2)p1, or —CO—O—(CH2)p1, wherein p1 is 2, 3, 4, 5 or 6, preferably 2 or 3, p2 and p3 are independently of each other 0, 1, 2 or 3 and, if Sp is —O—(CH2)p1—, —O—CO—(CH2)p1 or —CO—O—(CH2)p1 the O-atom or CO-group, respectively, is linked to a benzene ring of group M1, M2, or M3. Very preferably, if Sp is different from a single bond it is selected from —(CH2)2—, —(CH2)3—, —(CH2)4—, —O—(CH2)2—, —O—(CH2)3—, —O—CO—(CH2)2 and —CO—O—(CH)2—, wherein the O atom or the CO group is attached to a benzene ring of group M1, M2, or M3.
In a preferred embodiment of the invention the compounds of formula IA and its subformulae contain a spacer group Sp that is substituted by one or more, preferably by one, group La.
In the compounds of formula IA and its subformulae, Raa and Rbb preferably denote straight chain alkyl with 1 to 6 C atoms or branched alkyl with 3 to 6 C atoms. More preferably Raa and Rbb denote, independently of each other, methyl, ethyl, propyl and butyl, very preferably methyl or ethyl, most preferably methyl.
Further preferred are compounds of formula IA and its subformulae as described above and below, wherein Raa and Rbb together with the C atom to which they are attached form a cyclic alkyl group with 3 to 12 C atoms, very preferably a cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl group.
Very preferably the compounds of formula IA contain a group La selected from the following formulae
wherein the asterisk denotes the linkage to the adjacent group in the compound of formula IA.
In another preferred embodiment of the invention the compounds of formula IA and its subformulae contain a spacer group Sp that is a linear or branched alkylene with 1 to 12, preferably 1 to 7 C atoms which is substituted by one or more groups La. Preferred compounds of formula IA according to this preferred embodiment contain a group P—Sp— selected from the following formulae:
in which P and La are as defined in formula IA or have one of the meanings given above and below, and cc is 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3.
Preferred compounds of formula IA contain one or more groups P—Sp— selected from formulae SL1, SL2 and SL3, very preferably of formula SL1.
Preferably in the compounds of formula IA, M1 is selected of formula 1 or 2.
Preferred compounds of formula IA are selected from the following subformulae:
wherein P, Sp and L have the meanings given in formula IA or one of the preferred meanings as given above and below,
Very preferred compounds of formula I are selected from the following subformulae:
wherein P, Sp and La have the meanings given in formula IA or one of their preferred meanings as given above or below, Sp is preferably different from a single bond, Sp′ is a spacer group that is substituted by a group La, and is preferably selected from formulae SL1-SL4, and L′ has one of the meanings given for L above or below that is preferably different from La.
Very preferred compounds of subformulae IA-1-1 to IA-10-5 are those wherein all groups P are identical and denote acrylate or methacrylate, preferably methacrylate, furthermore those wherein Sp is, —(CH2)p1—, —(CH2)p1—O—, —(CH2)p1—O—CO— or —(CH2)p1—CO—O—, in which p1 is an integer from 1 to 12, preferably 1 to 6, and the O— or CO-group is connected to the benzene ring, furthermore those wherein Sp′ is selected from formula SL1, furthermore those wherein L′ is F.
Further preferred compounds of formula IA and its subformulae are selected from the following preferred embodiments, including any combination thereof:
Very preferred compounds of formula IA and its subformulae are selected from the following list:
wherein “Me” is methyl and “Et” is ethyl.
In a preferred embodiment the LC medium comprises one or more compounds of formula IB having two polymerizable groups, which are preferably selected from formula IB-D
wherein P and Sp have the meanings given in formula IB, L has one of the meanings given in formula IB which is different from P—Sp—, r1, r2 and r3 are independently of each other 0, 1, 2, 3 or 4, preferably 0, 1 or 2, very preferably 0 or 1, and k is 0 or 1.
Preferred compounds of formula IB-D are selected from the following subformulae
wherein P and Sp, L, r1, r2 and r3 have independently of each other one of the meanings given in formula IB-D or one of their preferred meanings as given above and below.
In the compounds of formula IB-D preferably at least one of r1, r2 and r3 is not 0. P is preferably acrylate or methacrylate, very preferably methacrylate. Preferably all groups P in the formulae IB-D, IB-D-1 and IB-D-2 have the same meaning, and very preferably denote methacrylate. Sp is preferably selected from —(CH2)2—, —(CH2)3—, —(CH2)4—, —O—(CH2)2—, —O—(CH2)3—, —O—CO—(CH2)2 and —CO—O—(CH)2—, wherein the O atom or the CO group is attached to the benzene ring. L is preferably selected from F, CH3, OCH3, OC2H5 and C2H5, very preferably from F.
Very preferred are the compounds of formula IB-D-1.
Further preferred compounds of formula IB-D are selected from the following subformulae
wherein P and L have one of the meanings as given in formula IB-D, and Sp′ has one of the meanings given for Sp that is different from a single bond. P is preferably acrylate or methacrylate, very preferably methacrylate. Preferably all groups P in the formulae IB-D-1-1 to IB-D-2-30 have the same meaning, and very preferably denote methacrylate. Sp′ is preferably selected from —(CH2)2—, —(CH2)3—, —(CH2)4—, —O—(CH2)2—, —O—(CH2)3—, —O—CO—(CH2)2 and —CO—O—(CH)2—, wherein the O atom or the CO group is attached to the benzene ring. L is preferably selected from F, CH3, OCH3, OC2H5 andC2H5, very preferably from F and OCH3.
Very preferred are the compounds of formula IB-D-1-1, 18-0-1-2, IB-D-1-3, 18-0-1-4, IB-D-1-5, 18-0-1-6, 18-0-2-1, 18-0-2-2, 18-0-2-12, 18-0-2-13 and IB-D-2-14 and their subformulae. Most preferred are the compounds of formula IB-D-1-1.
Very preferred compounds of formula IB-D are selected from the following subformulae:
Very preferred are the compounds of formula IBD1, IBD2, IBD4, IBD17, IBD21 and IBD22. Most preferred are the compounds of formula IBD1.
Further preferred are the compounds of formulae IBD1 to IBD16 wherein one or two of the methacrylate groups are each replaced by acrylate groups.
Further preferred compounds of formula IB-D are selected from Table D below, very preferably from the group consisting of RM-1, RM-2, RM-3, RM-4, RM-7 to RM-49 and RM-58 to RM-77, very preferably selected from the group consisting of RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-58, RM-64, RM-72 and RM-74.
In another preferred embodiment the LC medium comprises one or more polymerizable compounds of formula IB having three polymerizable groups, which are preferably selected from formula IB-T
wherein P, Sp, L, r1, r2 and k independently of each other have the meanings given in formula IB-D or one of their preferred meanings as given above and below, and r4 is 0, 1, 2 or 3, preferably 0, 1 or 2, very preferably 0 or 1.
Preferred compounds of formula IB-T are selected from the following subformulae
wherein P, Sp, L, r1, r2 and r4 have independently of each other one of the meanings given in formula IB-T or one of their preferred meanings as given above and below. Preferably at least one of r1, r2 and r4 is not 0. P is preferably acrylate or methacrylate, very preferably methacrylate. L is preferably selected from F, CH3, OCH3, OC2H5 and C2H5, very preferably from OCH3 or F. Preferably all groups P in the formulae IB-T and IB-T-1 to IB-T-6 have the same meaning, and very preferably denote methacrylate.
Very preferred are the compounds of formula IB-T-1, IB-T-4 and IB-T-5.
More preferred compounds of formula IB-T are selected from the following subformulae
wherein P, Sp and L have one of the meanings as given in formula IB-T and Sp′ has one of the meanings given for Sp that is different from a single bond. P is preferably acrylate or methacrylate, very preferably methacrylate. Preferably all groups P in the formulae IB-T-1-1 to IB-T-6-12 have the same meaning, and very preferably denote methacrylate. Sp′ is preferably selected from —(CH2)2—, —(CH2)3—, —(CH2)4—, —O—(CH2)2—, —O—(CH2)3—, —O—CO—(CH2)2 and —CO—O—(CH)2—, wherein the O atom or the CO group is attached to the benzene ring. L is preferably selected from F, CH3, OCH3, OC2H5 and C2H5, very preferably from F and OCH3.
Very preferred are the compounds of formula IB-T-1-1, IB-T-1-6, IB-T-4-1, IB-T-5-1 and their subformulae.
Very preferred compounds of formula IB-T are selected from the following subformulae:
Of the compounds of formula IBT1 to IB-T21 with two benzene rings very preferred are the compounds of formula IBT1, IBT2, IBT3, IBT8, IBT9, IBT10, IBT15, IBT16, IBT17. Most preferred are the compounds of formula IBT1, IBT2, IBT3, IBT8, IBT9 and IB10.
Of the compounds of formula IBT22 to IBT53 with three benzene rings very preferred are the compounds of formula IBT22 to IBT46. Most preferred are the compounds of formula IBT22, IBT28, IBT29, IBT35 and IBT36.
Further preferred are the compounds of formulae IBT1 to IBT53 wherein one or two of the methacrylate groups are each replaced by acrylate groups.
Further preferred are the compounds of formulae IBT1 to IBT53 wherein all methacrylate groups are each replaced by acrylate groups.
In another preferred embodiment the LC medium contains at least one compound of formula IC, which is at least monosubstituted by an alkenyl group Lb. Preferred compounds of formula IC of this preferred embodiment are selected from the following subformulae:
wherein P, Sp, L, r1, r2, r3 and r4 have the meanings given in formula IB-D and IB-T or one of the preferred meanings as given above and below, with r1+r2+r3+r4 ≥1, and wherein the compounds contain at least one group L that denotes Lb.
In the compounds of formulae IC-1 to IC-9 preferably Lb denotes —CH═CH2, —CH2—CH═CH2, —CH═CH—CH3, —CH═CH—CH═CH2 or —C(CH3)═CH2, very preferably —CH═CH2 or C(CH3)═CH2.
In the compounds of formulae IC-1 to IC-9 preferably P is acrylate or methacrylate, very preferably methacrylate. If Sp is different from a single bond, it is preferably selected from —(CH2)2—, —(CH2)3—, —(CH2)4—, —O—(CH2)2—, —O—(CH2)3—, —O—CO—(CH2)2— and —CO—O—(CH)2—, wherein the O atom or the CO group is attached to the benzene ring. L is preferably selected from F, CH3, OCH3, OC2H5 or C2H5, very preferably from OCH3 or F. Preferably all groups P in the formulae IC-1 to IC-9 have the same meaning, and very preferably denote methacrylate.
Preferred compounds of formulae IC-1 to IC-9 are selected from the following subformulae:
wherein A denotes Lb, P, Sp and L have the meanings given in formula IC or one of the preferred meanings given above and below, L may also have one of the meanings given for A.
Preferably in these compounds A is —CH═CH2, —CH2—CH═CH2, —CH═CH—CH3, —CH═CH—CH═CH2 or —C(CH3)═CH2, very preferably —CH═CH2 or C(CH3)=CH2. Further preferably in these compounds L denotes F, Cl, CH3, C2H5, OCH3 or OC2H5, very preferably F. Further preferably in these compounds L has one of the meanings given for A, preferably —CH═CH2 or C(CH3)=CH2. Further preferably in these compounds at least one group Sp denotes a single bond. Further preferably in these compounds P denotes acrylate or methacrylate, very preferably methacrylate.
Very preferred compounds of formulae IC-1 to IC-9 are selected from the following subformulae:
Further preferred are compounds of formula IC1 to IC46 wherein one, two or all of the methacrylate groups are each replaced by acrylate groups.
In a preferred embodiment the LC medium comprises at least one polymerizable compound of formula IA and/or formula IB and/or formula IC which have absorption in the range from 330 to 390 nm. Very preferably these compounds have an extinction coefficient of at least 0.5 at a wavelength in the range from 330 to 390 nm, more preferably in the range from 340 to 380 nm, very preferably in the range from 350 to 370 nm, most preferably in the range from 355 to 365 nm. The extinction coefficient and absorption wavelength are measured unless stated otherwise in a solution of the compound in DCM at a concentration of 3 g/L.
The total proportion of the polymerizable compounds of formulae IA, IB, IC and their subformulae in the LC medium according to the present invention is preferably from 0.05 to 3.0%, more preferably from 0.1 to 1.5%, very preferably from 0.1 to 0.9%.
In a first preferred embodiment of the present invention, the LC medium contains one or more, preferably exactly one, compound(s) of formula IA or its subformulae and one or more, preferably exactly one, compound(s) of formula IB or IC their subformulae, and preferably does not contain further polymerizable compounds.
Preferably, in the LC medium of this first preferred embodiment the proportion of the compound(s) of formula IA or its subformulae is from 0.01 to 1.0%, more preferably from 0.05 to 0.8%, very preferably from 0.1 to 0.6%, and the proportion of the compound(s) of formula IB or IC or their subformulae is from 0.01 to 1.0%, more preferably from 0.02 to 0.8%, very preferably from 0.05 to 0.5%.
In a second preferred embodiment of the present invention, the LC medium contains one or more, preferably exactly one, compound(s) of formula IA or its subformulae, one or more, preferably exactly one, compound(s) of formula IB or their subformulae, and one or more, preferably exactly one, compound(s) of formula IC or their subformulae, and preferably does not contain further polymerizable compounds.
More preferably the LC medium of this second preferred embodiment contains one or more, preferably exactly one, compound(s) of formula IA or its subformulae, one or more, preferably exactly one, compound(s) of formula IB-D or IB-T or their subformulae, and one or more, preferably exactly one, compond(s) selected from formulae IC-1 to IC-9 or their subformulae, and preferably does not contain further polymerizable compounds.
Preferably, in the LC medium of this second preferred embodiment the proportion of the compound(s) of formula IA or its subformulae is from 0.01 to 1.0%, more preferably from 0.05 to 0.8%, very preferably from 0.1 to 0.6%, the total proportion of the compound(s) of formula IB-D and IB-T or their subformulae is from 0.01 to 1.0%, more preferably from 0.05 to 0.8%, very preferably from 0.1 to 0.6%, and the total proportion of the compound(s) of the formulae IC-1 to IC-9 or their subformulae is from 0.01 to 1.0%, more preferably from 0.02 to 0.8%, very preferably from 0.05 to 0.5%.
In another preferred embodiment the LC medium comprises, in addition to the polymerizable compounds of formulae IA, IB, IC and their subformulae, at least one further polymerizable compound.
Preferred further polymerizable compounds are selected from Table D below, especially those selected from the group consisting of formulae RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-64, RM-74, RM-76, RM-88, RM-102, RM-103, RM-109, RM-117, RM-120, RM-121, RM-122, R-139, RM-142, RM-143, RM-148 to RM-158, RM-164, RM-165 and RM-166 to RM-178.
The proportion of these further polymerizable compounds in the LC medium is preferably from 0.01 to 1.0%, more preferably from 0.05 to 0.6%.
The polymerizable compounds can be prepared analogously to processes known to the person skilled in the art and described in standard works of organic chemistry, such as, for example, in Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart.
For example, acrylic or methacrylic esters can be prepared by esterification of the corresponding alcohols with acid derivatives like, for example, (meth)acryloyl chloride or (meth)acrylic anhydride in the presence of a base like pyridine or triethyl amine, and 4-(N,N-dimethylamino)pyridine (DMAP). Alternatively the esters can be prepared by esterification of the alcohols with (meth)acrylic acid in the presence of a dehydrating reagent, for example according to Steglich with dicyclohexylcarbodiimide (DCC), N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) or N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride and DMAP.
The invention furthermore relates to an LC medium or LC display as described above, wherein the polymerizable compounds are present in polymerized form.
The LC display is preferably a PS-VA, PS-IPS, PS-FFS, or SA-VA display.
For the production of PSA or polymer stabilised SA displays, the polymerizable compounds contained in the LC medium are polymerized by in-situ polymerization in the LC medium between the substrates of the LC display, preferably while a voltage is applied to the electrodes.
The structure of the displays according to the invention corresponds to the usual geometry for PSA displays, as described in the prior art cited at the outset. Geometries without protrusions are preferred, in particular those in which, in addition, the electrode on the colour filter side is unstructured and only the electrode on the TFT side has slots. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006/0066793 A1.
A preferred PSA type LC display of the present invention comprises:
The first and/or second alignment layer controls the alignment direction of the LC molecules of the LC layer. For example, in PS-VA displays the alignment layer is selected such that it imparts to the LC molecules homeotropic (or vertical) alignment (i.e. perpendicular to the surface) or tilted alignment. Such an alignment layer may for example comprise a polyimide, which may also be rubbed, or may be prepared by a photoalignment method.
The LC layer with the LC medium can be deposited between the substrates of the display by methods that are conventionally used by display manufacturers, for example the so-called one-drop-filling (ODF) method. The polymerizable component of the LC medium is then polymerized for example by UV photopolymerization. The polymerization can be carried out in one step or in two or more steps.
The PSA display may comprise further elements, like a colour filter, a black matrix, a passivation layer, optical retardation layers, transistor elements for addressing the individual pixels, etc., all of which are well known to the person skilled in the art and can be employed without inventive skill.
The electrode structure can be designed by the skilled person depending on the individual display type. For example for PS-VA displays a multi-domain orientation of the LC molecules can be induced by providing electrodes having slits and/or bumps or protrusions in order to create two, four or more different tilt alignment directions.
Upon polymerization the polymerizable compounds form a copolymer, which causes a certain tilt angle of the LC molecules in the LC medium. Without wishing to be bound to a specific theory, it is believed that at least a part of the crosslinked polymer, which is formed by the polymerizable compounds, will phase-separate or precipitate from the LC medium and form a polymer layer on the substrates or electrodes, or the alignment layer provided thereon. Microscopic measurement data (like SEM and AFM) have confirmed that at least a part of the formed polymer accumulates at the LC/substrate interface.
The polymerization can be carried out in one step. It is also possible firstly to carry out the polymerization, optionally while applying a voltage, in a first step in order to produce a tilt angle, and subsequently, in a second polymerization step without an applied voltage, to polymerize or crosslink the compounds which have not reacted in the first step (“end curing”).
Suitable and preferred polymerization methods are, for example, thermal or photopolymerization, preferably photopolymerization, in particular UV induced photopolymerization, which can be achieved by exposure of the polymerizable compounds to UV radiation.
A preferred process of preparing a PSA display includes one or more of the following features:
Both using lower intensity and a UV shift to longer wavelengths protect the organic layer against damage that may be caused by the UV light.
A preferred embodiment of the present invention relates to a process for preparing a PSA display as described above and below, comprising one or more of the following features:
This preferred process can be carried out for example by using the desired UV lamps or by using a band pass filter and/or a cut-off filter, which are substantially transmissive for UV light with the respective desired wavelength(s) and are substantially blocking light with the respective undesired wavelengths. For example, when irradiation with UV light of wavelengths λ of 300-400 nm is desired, UV exposure can be carried out using a wide band pass filter being substantially transmissive for wavelengths 300 nm < λ < 400 nm. When irradiation with UV light of wavelength λ of more than 340 nm is desired, UV irradiation can be carried out using a cut-off filter being substantially transmissive for wavelengths λ > 340 nm.
Preferably UV irradiation is carried out using a UV-LED lamp.
The use of UV-LED lamps, which have with only one narrow emission peak, in the PSA process provides several advantages, like for example a more effective optical energy transfer to the polymerizable compounds in the LC medium, depending on the choice of the suitable polymerizable compounds that shows absorption at the emission wavelength of the LED lamp. This allows to reduce the UV intensity and/or the UV irradiation time, thus enabling a reduced tact time and savings in energy and production costs. Another advantage is that the narrow emission spectrum of the lamp allows an easier selection of the appropriate wavelength for photopolymerization.
Very preferably the UV light source is an UV-LED lamp emitting a wavelength in the range from 340 to 400 nm, more preferably in the range from 350 to 390 nm, very preferably in the range from 360 to 380 nm, most preferably in the range from 360 to 368 nm. UV-LED lamps emitting UV light with a wavelength of 365 nm are especially preferred.
Preferably the UV-LED lamp emits light having an emission peak with a full width half maximum (FWHM) of 30 nm or less.
UV-LED lamps are commercially available, for example from Dr. Hoenle AG, Germany or Primelite GmbH, Germany, or IST Metz GmbH, Germany, with emission wavelengths e.g. of 365, 385, 395 and 405 nm.
This preferred process enables the manufacture of displays by using longer UV wavelengths, thereby reducing or even avoiding the hazardous and damaging effects of short UV light components.
UV radiation energy is in general from 6 to 100 J, depending on the production process conditions.
The LC medium according to the present invention may additionally comprise one or more further components or additives, preferably selected from the list including but not limited to co-monomers, chiral dopants, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricating agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments and nanoparticles.
The LC medium has preferably a nematic LC phase.
In a preferred embodiment the LC medium contains one or more polymerization initiators. Suitable conditions for the polymerization and suitable types and amounts of initiators are known to the person skilled in the art and are described in the literature. Suitable for free-radical polymerization are, for example, the commercially available photoinitiators Irgacure651®, Irgacure184®, Irgacure907®, Irgacure369® or Darocure1173® (Ciba AG). If a polymerization initiator is employed, its proportion is preferably 0.001 to 5% by weight, particularly preferably 0.001 to 1% by weight.
The polymerizable compounds according to the invention are also suitable for polymerization without an initiator, which is accompanied by considerable advantages, such as, for example, lower material costs and in particular less contamination of the LC medium by possible residual amounts of the initiator or degradation products thereof.
The polymerization can thus also be carried out without the addition of an initiator. Thus, in another preferred embodiment, the LC medium does not contain a polymerization initiator.
In another preferred embodiment the LC medium additionally comprises one or more stabilisers in order to prevent undesired spontaneous polymerization of the RMs, for example during storage or transport. Suitable types and amounts of stabilisers are known to the person skilled in the art and are described in the literature. Particularly suitable are, for example, the commercially available stabilisers from the Irganox® series (Ciba AG), such as, for example, Irganox® 1076. If stabilisers are employed, their proportion, based on the total amount of RMs or the polymerizable component (component A), is preferably 10-50,000 ppm, particularly preferably 50-5,000 ppm.
In a preferred embodiment the LC medium contains one or more chiral dopants, preferably in a concentration from 0.01 to 1% by weight, very preferably from 0.05 to 0.5% by weight. The chiral dopants are preferably selected from the group consisting of compounds from Table B below, very preferably from the group consisting of R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011, and R- or S-5011.
In another preferred embodiment the LC media contain a racemate of one or more chiral dopants, which are preferably selected from the chiral dopants mentioned in the previous paragraph.
In another preferred embodiment of the present invention the LC media contain one or more further stabilisers, preferably selected from the the group consisting of the following formulae
Preferred stabilisers of formula S3 are selected from formula S3A
wherein n2 is an integer from 1 to 12, and wherein one or more H atoms in the group (CH2)n2 are each optionally replaced by methyl, ethyl, propyl, butyl, pentyl or hexyl.
Very preferred stabilisers are selected from the group consisting of the following formulae
In a preferred embodiment the LC medium comprises one or more stabilisers selected from the group consisting of formulae S1-1, S2-1, S3-1, S3-1 and S3-3.
In a preferred embodiment the LC medium comprises one or more stabilisers selected from Table C below.
Preferably the proportion of stabilisers, like those of formula S1—S3, in the LC medium is from 10 to 500 ppm,very preferably from 20 to 100 ppm.
In another preferred embodiment the LC medium according to the present invention contains a self alignment (SA) additive, preferably in a concentration of 0.1 to 2.5 %.
In a preferred embodiment the SA-VA display according to the present invention does not contain a polyimide alignment layer. In another preferred embodiment the SA-VA display according to preferred embodiment contains a polyimide alignment layer.
Preferred SA additives for use in this preferred embodiment are selected from compounds comprising a mesogenic group and a straight-chain or branched alkyl side chain that is terminated with one or more polar anchor groups selected from hydroxy, carboxy, amino or thiol groups.
Further preferred SA additives contain one or more polymerizable groups which are attached, optionally via spacer groups, to the mesogenic group.
These polymerizable SA additives can be polymerized in the LC medium under similar conditions as applied for the RMs in the PSA process.
Suitable SA additives to induce homeotropic alignment, especially for use in SA-VA mode displays, are disclosed for example in US 2013/0182202 A1, US 2014/0838581 A1, US 2015/0166890 A1 and US 2015/0252265 A1.
In another preferred embodiment an LC medium or a polymer stabilised SA-VA display according to the present invention contains one or more self alignment additives selected from Table E below.
In another preferred embodiment the LC medium according to the present invention contains one or more SA additives, preferably selected from formula II or its subformulae or selected from Table E, in a concentration from 0.1 to 5%, very preferably from 0.2 to 3%, most preferably from 0.2 to 1.5%.
Besides the polymerizable compounds and additives described above, the LC medium for use in the LC displays according to the invention comprises an LC mixture (“host mixture”) comprising one or more, preferably two or more LC compounds which are selected from low-molecular-weight compounds that are unpolymerizable, and at least one of which is a compound of formula II. These LC compounds are selected such that they stable and/or unreactive to a polymerization reaction under the conditions applied to the polymerization of the polymerizable compounds.
Particularly preferred embodiments of such an LC medium are shown below.
Preferably the LC medium contains one or more compounds of formula II selected from the group consisting of compounds of the formulae IIA, IIB, IIC and IID
in which
Preferred compounds of the formulae IIA, IIB, IIC and IID are those wherein R2B denotes an alkyl or alkoxy radical having up to 15 C atoms, and very preferablydenotes (O)CvH2v+1 wherein (O) is an oxygen atom or a single bond and v is 1, 2, 3, 4, 5 or 6.
Further preferred compounds of the formulae IIA, IIB, IIC and IID are those wherein R2A or R2B denotes or contains cycloalkyl or cycloalkoxy radical, preferably selected from the group consisting of
wherein S1 is C1-5-alkylene or C2-5-alkenylene and S2 is H, C1-7-alkyl or C2-7-alkenyl, and very preferably selected from the group consisting of
Further preferred compounds of the formulae IIA, IIB, IIC and IID are indicated below:
in which the parameter a denotes 1 or 2, alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms, and (O) denotes an oxygen atom or a single bond. Alkenyl preferably denotes CH2═CH—, CH2═CHCH2CH2—, CH3—CH═CH—, CH3—CH2—CH═CH—, CH3—(CH2)2—CH═CH—, CH3—(CH2)3—CH═CH— or CH3—CH═CH—(CH2)2—.
Particularly preferred LC medium according to the invention comprises one or more compounds of the formulae IIA-2, IIA-8, IIA-10, IIA-16, II-18, IIA-40, IIA-41, IIA-42, IIA-43, IIB-2, IIB-10, IIB-16, IIC-1, and IID-4.
The proportion of compounds of the formulae IIA and/or IIB in the mixture as a whole is preferably at least 20 % by weight.
In another preferred embodiment the LC medium comprises one or more compounds of formula III
in which
Z1 on each occurrence independently of one another denotes —COO—, —O—CO—, —CF2O— , —OCF2—, —CH2O—, —OCH2—, —CH2—, —CH2CH2—, —(CH2)4—, —CH═CH—CH2O—, —C2F4—, —CH2CF2—, —CF2CH2 —, —CF═CF—, —CH═CF—, —CF═CH—, —CH═CH—, —C≡C— or a single bond, and
In a preferred embodiment of the present invention the LC medium comprises one or more compounds of the formula III-1 and/or III-2
in which the occurring groups have the same meanings as given under formula III above and preferably
R11 and R12 each, independently of one another, an alkyl, alkenyl or alkoxy radical having up to 15 C atoms, more preferably one or both of them denote an alkoxy radical and
L11 and L12 each preferably denote F.
In another preferred embodiment the LC medium comprises one or more compounds of the formula III-1 selected from the group of compounds of formulae III-1-1 to III-1-10, preferably of formula III-1-6,
in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L11 and L12 each, independently of one another, denote F or Cl, preferably both F.
In another preferred embodiment the LC medium comprises one or more compounds of the formula III-2 selected from the group of compounds of formulae III-2-1 to III-2-10, preferably of formula III-2-6,
in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L1 and L2 each, independently of one another, denote F or Cl, preferably both F.
In another preferred embodiment of the present invention the LC medium comprises one or more compounds of the formula IIIA-1 and/or IIIA-2
in which L11 and L12 have the same meanings as given under formula III, (O) denotes O or a single bond,
The compounds of formula IIIA-1 and/or IIIA-2 are contained in the LC medium either alternatively or additionally to the compounds of formula III, preferably additionally.
Very preferred compounds of the formulae IIIA-1 and IIIA-2 are the following:
in which alkoxy denotes a straight-chain alkoxy radical having 1-6 C atoms.
In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of formula III-3
in which
R11, R12 identically or differently, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, in which one or more CH2 groups in these radicals are each optionally replaced, independently of one another, by —C≡C—, —CF2O—, —OCF2—, —CH═CH—,
—O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may each be replaced by halogen.
The compounds of formula III-3 are preferably selected from the group of compounds of the formulae III-3-1 to III-3-10:
in which R12 denotes alkyl having 1 to 7 C-atoms, preferably ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl.
In another preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formulae III-4 to III-6, preferably of formula III-5,
in which the parameters have the meanings given in formula III, R11 preferably denotes straight-chain alkyl and R12 preferably denotes alkoxy, each having 1 to 7 C atoms.
In another preferred embodiment the LC medium comprises one or more compounds of the formula I selected from the group of compounds of formulae III-7 to III-9, preferably of formula III-8,
in which the parameters have the meanings given in formula III, R11 preferably denotes straight-chain alkyl and R12 preferably denotes alkoxy each having 1 to 7 C atoms.
In a preferred embodiment, the medium comprises one or more compounds of the formula IV,
in which
R41 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably an n-alkyl radical, particularly preferably having 2, 3, 4 or 5 C atoms, and
R42 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably a vinyl radical or a 1-propenyl radical and in particular a vinyl radical.
The compounds of the formula IV are preferably selected from the group of the compounds of the formulae IV-1 to IV-4,
in which
Preferably, the LC medium comprises one or more compounds selected from the compounds of the formulae IV-1-1 to IV-1-4
Very preferably, the LC medium according to the invention comprises one or more compounds of the formulae IV-2-1 and/or IV-2-2
Very preferably, the LC medium according to the invention comprises a compound of formula IV-3, in particular selected from the compounds of the formulae IV-3-1 to IV-3-4
Very preferably, the LC medium according to the invention comprises a compound of formula IV-4, in particular selected from the compounds of the formulae IV-4-1 and IV-4-2
The LC medium preferably additionally comprises one or more compounds of the formula IVa,
in which
R41 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably an n-alkyl radical, particularly preferably having 2, 3, 4 or 5 C atoms, and
R42 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably a vinyl radical or a 1-propenyl radical and in particular a vinyl radical, and
denotes
Z4 denotes a single bond, —CH2CH2—, —CH═CH—, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —COO—, —OCO—, —C2F4—, —C4H8— or —CF═CF—.
Preferred compounds of the formula IVa are indicated below:
in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms.
The LC medium according to the invention preferably comprises at least one compound of the formula IVa-1 and/or formula IVa-2.
The proportion of compounds of the formula IVa in the mixture as a whole is preferably at least 5 % by weight
Preferably, the LC medium comprises one or more compounds of formula IVb-1 to lVb-3
in which
alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and
alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2 to 6 C atoms.
The proportion of the biphenyls of the formulae IV-1 to IV-3 in the mixture as a whole is preferably at least 3 % by weight, in particular ≥ 5 % by weight.
Of the compounds of the formulae IVb-1 to IVb-3, the compounds of the formula IVb-2 are particularly preferred.
Particularly preferred biphenyls are
in which alkyl* denotes an alkyl radical having 1 to 6 C atoms and preferably denotes n-propyl.
The LC medium according to the invention particularly preferably comprises one or more compounds of the formulae IVb-1-1 and/or IVb-2-3.
In a preferred embodiment, the LC medium comprises one or more compounds of formula V
in which
R51 and R52 independently of one another, denote alkyl having 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C atoms, alkoxy having 1 to 7 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 C atoms, alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms, preferably having 2 to 4 C atoms, preferably alkenyloxy,
identically or differently, denote
in which
preferably denotes
Z51 , Z52 each, independently of one another, denote —CH2—CH2—, —CH2—O—,—CH═CH—, —C═C—, —COO— or a single bond, preferably —CH2—CH2—, —CH2—O— or a single bond and particularly preferably a single bond, and
n is 1 or 2.
The compounds of formula V are preferably selected from the compounds of the formulae V-1 to V-16:
in which R1 and R2 have the meanings indicated for R51 and R52 above. R1 and R2 preferably each, independently of one another, denote straight-chain alkyl or alkenyl.
Preferred LC media comprise one or more compounds of the formulae V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15, and/or V-16
LC media according to the invention very particularly preferably comprise the compounds of the formula V-10, V-12, V-16 and/or IV-1, in particular in amounts of 5 to 30 %.
Preferred compounds of the formulae V-10 are indicated below:
The LC medium according to the invention particularly preferably comprises the tricyclic compounds of the formula V-10a and/or of the formula V-10b in combination with one or more bicyclic compounds of the formulae IV-1 The total proportion of the compounds of the formulae V-10a and/or V-10b in combination with one or more compounds selected from the bicyclohexyl compounds of the formula IV-1 is 5 to 40 %, very particularly preferably 15 to 35%.
Very particularly preferred LC media comprise compounds V-10a and IV-1-1
The compounds V-10a and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35 %, particularly preferably 15 to 25 % and especially preferably 18 to 22 %, based on the mixture as a whole.
Very particularly preferred LC media comprise the compounds V-10b and IV-1-1:
The compounds V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35 %, particularly preferably 15 to 25 % and especially preferably 18 to 22 %, based on the mixture as a whole.
Very particularly preferred LC media comprise the following three compounds:
The compounds V-10a, V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35 %, particularly preferably 15 to 25 % and especially preferably 18 to 22 %, based on the mixture as a whole.
Preferred LC media comprise at least one compound selected from the group of the compounds
in which R41 and R42, and R51 and R52 have the meanings indicated above. Preferably in the compounds V-6, V-7 and IV-1, R41 and R51 denotes alkyl or alkenyl having 1 to 6 or 2 to 6 C atoms, respectively, and R42 and R52 denotes alkenyl having 2 to 6 C atoms.
Preferred LC media comprise at least one compound of the formulae V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b:
in which alkyl denotes an alkyl radical having 1 to 6 C atoms and alkenyl denotes an alkenyl radical having 2 to 6 C atoms.
The compounds of the formulae V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b are preferably present in the LC media according to the invention in amounts of 1 to 40 % by weight, preferably 5 to 35 % by weight and very particularly preferably 10 to 30 % by weight.
In a preferred embodiment of the present invention the LC medium additionally comprises one or more compounds of the formulae VI-1 to VI-9
in which
Particular preference is given to LC media comprising at least one compound of the formula V1-9.
In a preferred embodiment of the present invention the LC medium additionally comprises one or more compounds of the formulae VII-1 to VII-25,
in which
R denotes a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, (O) denotes —O— or a single bond, X denotes F, Cl, OCF3 or OCHF2, Lx denotes H or F, m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4.
R preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy.
X preferably denotes F or OCF3, very preferably F.
The LC medium according to the invention preferably comprises the terphenyls of the formulae VII-1 to VII-25 in amounts of 2 to 30 % by weight, in particular 5 to 20 % by weight.
Particular preference is given to compounds of the formulae VII-1, VII-2, VII-4, VII-20, VII-21, and VII-22 wherein X denotes F. In these compounds, R preferably denotes alkyl, furthermore alkoxy, each having 1 to 5 C atoms. In the compounds of the formula VII-20, R preferably denotes alkyl or alkenyl, in particular alkyl. In the compounds of the formula VII-21, R preferably denotes alkyl. In the compounds of the formulae VII-22 to VII-25, X preferably denotes F.
The terphenyls of formula VII-1 to VII-25 are preferably employed in the LC media according to the invention if the Δn value of the mixture is to be ≥ 0.1. Preferred LC media comprise 2 to 20 % by weight of one or more terphenyl compounds selected from the group of the compounds of formulae VII-1 to VII-25.
Further preferred embodiments are listed below:
a) LC medium comprising at least one compound of the formulae Z-1 to Z-7,
in which Rand (O) have the meanings indicated above for formulae VII-1 to VII-25, and alkyl denotes a straight-chain alkyl radical having 1 to 6 C atoms.
b) Preferred LC media according to the invention comprise one or more substances which contain a tetrahydronaphthyl or naphthyl unit, such as, for example, the compounds of the formulae N-1 to N-5,
in which R1N and R2N each, independently of one another, have the meanings indicated for R2A in formula IIA, preferably denote straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and
Z1 and Z2 each, independently of one another, denote —C2H4—, —CH═CH—, —(CH2)4—, —(CH2)3O—, —O(CH2)3—, —CH═CHCH2CH2—, —CH2CH2CH═CH—, —CH2O—, —OCH2—, —COO—, —OCO—, —C2F4—, —CF═CF—, —CF═CH—, —CH═CF—, —CF2O—, —OCF2—, —CH2— or a single bond.
c) Preferred LC media comprise one or more compounds selected from the group of the difluorodibenzochroman compounds of the formula BC, chromans of the formula CR, and fluorinated phenanthrenes of the formulae PH-1 and PH-2,
in which
RB1, RB2, RCR1, RCR2, R1, R2 each, independently of one another, have the meaning of R2A in formula IIA. c is 0, 1 or 2. R1 and R2 preferably, independently of one another, denote alkyl or alkoxy having 1 to 6 C atoms.
The LC media according to the invention preferably comprise the compounds of the formulae BC, CR, PH-1, and/or PH-2 in amounts of 3 to 20 % by weight, in particular in amounts of 3 to 15 % by weight.
Particularly preferred compounds of the formulae BC and CR are the compounds BC-1 to BC-7 and CR-1 to CR-5,
in which
alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and
alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2 to 6 C atoms.
Very particular preference is given to LC media comprising one, two or three compounds of the formula BC-2.
d) Preferred LC media comprise one or more indane compounds of the formula In,
in which
Preferred compounds of the formula In are the compounds of the formulae In-1 to In-16 indicated below:
Particular preference is given to the compounds of the formulae In-1, In-2, In-3 and In-4.
The compounds of the formula In and the sub-formulae In-1 to In-16 are preferably employed in the LC media according to the invention in concentrations ≥ 5 % by weight, in particular 5 to 30 % by weight and very particularly preferably 5 to 25 % by weight.
e) Preferred LC media additionally comprise one or more compounds of the formulae L-1 to L-5,
in which
R, R1 , and R2 each, independently of one another, have the meanings indicated for R2A in formula IIA above, (O) is an oxygen atom or a single bond, and alkyl denotes an alkyl radical having 1 to 6 C atoms. The parameter s denotes 1 or 2.
The compounds of the formulae L-1 to L-5 are preferably employed in concentrations of 5 to 50 % by weight, in particular 5 to 40 % by weight and very particularly preferably 10 to 40 % by weight.
f) Preferred LC media additionally comprise one or more compounds of formula IIA-Y
in which R11 and R12 have one of the meanings given for R2A in formula IIA above, and L1 and L2, identically or differently, denote F or Cl.
Preferred compounds of the formula IIA-Y are selected from the group consisting of the following subformulae
in which, Alkyl and Alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, Alkoxy and Alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, Alkenyl and Alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, and O denotes an oxygen atom or a single bond. Alkenyl and Alkenyl* preferably denote CH2═CH—, CH2═CHCH2CH2—, CH3—CH═CH—, CH3—CH2—CH═CH—, CH3—(CH2)2—CH═CH—, CH3—(CH2)3—CH═CH— or CH3—CH═CH—(CH2)2—.
Particularly preferred compounds of the formula IIA-Y are selected from the group consisting of following subformulae:
in which Alkoxy and Alkoxy* have the meanings defined above and preferably denote methoxy, ethoxy, n- propyloxy, n-butyloxy or n-pentyloxy.
g) LC medium which additionally comprises one or more quaterphenyl compounds selected from the following formula:
wherein
Preferred compounds of formula Q are those wherein RQ denotes straight-chain alkyl with 2 to 6 C-atoms, very preferably ethyl, n-propyl or n-butyl.
Preferred compounds of formula Q are those wherein LQ3 and LQ4 are F. Further preferred compounds of formula Q are those wherein LQ3, LQ4 and one or two of LQ1 and LQ2 are F.
Preferred compounds of formula Q are those wherein XQ denotes F or OCF3, very preferably F.
The compounds of formula Q are preferably selected from the following subformulae
wherein RQ has one of the meanings of formula Q or one of its preferred meanings given above and below, and is preferably ethyl, n-propyl or n-butyl.
Especially preferred are compounds of formula Q1, in particular those wherein RQ is n-propyl.
Preferably the proportion of compounds of formula Q in the LC host mixture is from >0 to ≤5% by weight, very preferably from 0.05 to 2% by weight, more preferably from 0.1 to 1% by weight, most preferably from 0.1 to 0.8% by weight.
Preferably the LC medium contains 1 to 5, preferably 1 or 2 compounds of formula Q.
The addition of quaterphenyl compounds of formula Q to the LC host mixture enables to reduce ODF mura, whilst maintaining high UV absorption, enabling quick and complete polymerization, enabling strong and quick tilt angle generation, and increasing the UV stability of the LC medium.
Besides, the addition of compounds of formula Q, which have positive dielectric anisotropy, to the LC medium with negative dielectric anisotropy allows a better control of the values of the dielectric constants εll and ε⊥, and in particular enables to achieve a high value of the dielectric constant εll while keeping the dielectric anisotropy Δε constant, thereby reducing the kick-back voltage and reducing image sticking.
The LC media according to the invention preferably comprise
In particular, the medium comprises
The invention furthermore relates to an electro-optical display having active-matrix addressing, characterised in that it contains, as dielectric, a LC medium according to claim 1 and wherein the display is a VA, SA-VA, IPS, U-IPS, FFS, UB-FFS, SA-FFS, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA, PS-TN, polymer stabilised SA-VA or polymer stabilised SA-FFS display.
It is advantageous for the LC medium according to the invention to preferably have a nematic phase from ≤ -20° C. to ≥ 70° C., particularly preferably from ≤ -30° C. to ≥ 80° C., very particularly preferably from ≤ -40° C. to ≥ 90° C.
The medium according to the invention has a clearing temperature of 70° C. or more, preferably of 74° C. or more.
The expression “have a nematic phase” here means on the one hand that no smectic phase and no crystallisation are observed at low temperatures at the corresponding temperature and on the other hand that clearing still does not occur on heating from the nematic phase. The investigation at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storage in test cells having a layer thickness corresponding to the electro-optical use for at least 100 hours. If the storage stability at a temperature of -20° C. in a corresponding test cell is 1000 h or more, the medium is referred to as stable at this temperature. At temperatures of -30° C. and -40° C., the corresponding times are 500 h and 250 h respectively. At high temperatures, the clearing point is measured by conventional methods in capillaries.
The liquid-crystal mixture preferably has a nematic phase range of at least 60 K and a flow viscosity v20 of at most 30 mm2 . s-1 at 20° C.
The mixture is nematic at a temperature of -20° C. or less, preferably at -30° C. or less, very preferably at -40° C. or less.
The values of the birefringence Δn in the liquid-crystal mixture are generally between 0.07 and 0.16, preferably between 0.08 and 0.15, very preferably between 0.09 and 0.14.
In a preferred embodiment of the present invention, the medium has a birefringence in the range of from 0.090 to 0.110, preferably from 0.095 to 0.105, in particular from 0.100 to 0.105.
In another preferred embodiment, the medium according to the invention has a birefringence of 0.120 or more, preferably in the range of from 0.125 to 0.145, more preferably from 0.130 to 0.140.
The liquid-crystal mixture according to the invention has a dielectric anisotropy Δε of -1.5 to -8.0, preferably of -2.0 to - 4.0, in particular -2.5 to -3.5,
The rotational viscosity γ1 at 20° C. is preferably≤ 120 mPa·s, in particular ≤ 100 mPa·s.
In a preferred embodiment, the rotational viscosity γ1 at 20° C. is ≤ 100 mPa·s, in particular ≤ 95 mPa·s.
The liquid-crystal media according to the invention have relatively low values for the threshold voltage (V0). They are preferably in the range from 1.7 V to 3.0 V, particularly preferably ≤ 2.7 V and very particularly preferably ≤ 2.5 V.
For the present invention, the term “threshold voltage” relates to the capacitive threshold (V0), also called the Freedericks threshold, unless explicitly indicated otherwise.
In addition, the liquid-crystal media according to the invention have high values for the voltage holding ratio in liquid-crystal cells.
In general, liquid-crystal media having a low addressing voltage or threshold voltage exhibit a lower voltage holding ratio than those having a higher addressing voltage or threshold voltage and vice versa.
For the present invention, the term “dielectrically positive compounds” denotes compounds having a Δε > 1.5, the term “dielectrically neutral compounds” denotes those having -1.5 ≤ Δε ≤ 1.5 and the term “dielectrically negative compounds” denotes those having Δε < -1.5. The dielectric anisotropy of the compounds is determined here by dissolving 10 % of the compounds in a LC host and determining the capacitance of the resultant mixture in at least one test cell in each case having a layer thickness of 20 µm with homeotropic and with homogeneous surface alignment at 1 kHz. The measurement voltage is typically 0.5 V to 1.0 V, but is always lower than the capacitive threshold of the respective liquid-crystal mixture investigated.
All temperature values indicated for the present invention are in °C.
The LC media according to the invention are suitable for all VA-TFT (vertical alignment-thin film transistor) applications, such as, for example, VAN (vertically aligned nematic), MVA (multidomain VA), (S)-PVA (super patterned VA), ASV (advanced super view, or axially symmetric VA), PSA (polymer sustained VA) and PS-VA (polymer stabilized VA). They are furthermore suitable for IPS (in-plane switching) and FFS (fringe field switching) applications having negative Δε.
The nematic LC media in the displays according to the invention generally comprise two components A and B, which themselves consist of one or more individual compounds.
Component A has significantly negative dielectric anisotropy and gives the nematic phase a dielectric anisotropy of ≤ -0.5. Besides one or more compounds of the formula IA and one or more compounds of formula Ib and/or formula IC, it preferably comprises the compounds of the formulae IIA, IIB and/or IIC, furthermore one or more compounds of the formula IV-1.
The proportion of component A is preferably between 45 and 100 %, in particular between 60 and 85 %.
For component A, one (or more) individual compound(s) which has (have) a value of Δε ≤ -0.8 is (are) preferably selected. This value must be more negative, the smaller the proportion A in the mixture as a whole.
Component B has pronounced nematogeneity and a flow viscosity of not greater than 30 mm2. s-1, preferably not greater than 25 mm2. s-1, at 20° C.
A multiplicity of suitable materials is known to the person skilled in the art from the literature. Particular preference is given to compounds of the formula 0-17.
Particularly preferred individual compounds in component B are extremely low-viscosity nematic liquid crystals having a flow viscosity of not greater than 18 mm2 · S-1, preferably not greater than 12 mm2 · s-1, at 20° C.
Component B is monotropically or enantiotropically nematic, has no smectic phases and is able to prevent the occurrence of smectic phases down to very low temperatures in LC media. For example, if various materials of high nematogeneity are added to a smectic liquid-crystal mixture, the nematogeneity of these materials can be compared through the degree of suppression of smectic phases that is achieved.
The mixture may optionally also comprise a component C, comprising compounds having a dielectric anisotropy of Δε ≥1.5. These so-called positive compounds are generally present in a mixture of negative dielectric anisotropy in amounts of ≤ 20 % by weight, based on the mixture as a whole.
Besides one or more compounds of the formula I1, I2 and optionally I3, the medium preferably comprises 4 to 15, in particular 5 to 12, and particularly preferably < 10, compounds of the formulae IIA, IIB and/or IIC and optionally one or more compounds of the formula IV-1
Besides compounds of the formula I1, I2 and optionally I3 and the compounds of the formulae IIA, IIB and/or IIC and optionally IV-1, other constituents may also be present, for example in an amount of up to 45 % of the mixture as a whole, but preferably up to 35 %, in particular up to 10 %.
The other constituents are preferably selected from nematic or nematogenic substances, in particular known substances, from the classes of the azoxybenzenes, benzylideneanilines, biphenyls, terphenyls, phenyl or cyclohexyl benzoates, phenyl or cyclohexyl cyclohexanecarboxylates, phenylcyclohexanes, cyclohexylbiphenyls, cyclohexylcyclohexanes, cyclo-hexylnaphthalenes, 1,4-biscyclohexylbiphenyls or cyclohexylpyrimidines, phenyl- or cyclohexyldioxanes, optionally halogenated stilbenes, benzyl phenyl ethers, tolanes and substituted cinnamic acid esters.
The most important compounds which are suitable as constituents of liquid-crystal phases of this type can be characterised by the formula OC
in which L and E each denote a carbo- or heterocyclic ring system from the group formed by 1,4-disubstituted benzene and cyclohexane rings, 4,4′-disubstituted biphenyl, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidine and 1,3-dioxane rings, 2,6-disubstituted naphthalene, di- and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline,
or a C—C single bond, Q denotes halogen, preferably chlorine, or —CN, and R20 and R21 each denote alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyl-oxy having up to 18, preferably up to 8, carbon atoms, or one of these radicals alternatively denotes CN, NC, NO2, NCS, CF3, SF5, OCF3, F, Cl or Br.
In most of these compounds, R20 and R21 are different from one another, one of these radicals usually being an alkyl or alkoxy group. Other variants of the proposed substituents are also common. Many such substances or also mixtures thereof are commercially available. All these substances can be prepared by methods known from the literature.
It goes without saying for the person skilled in the art that the VA, IPS or FFS mixture according to the invention may also comprise compounds in which, for example, H, N, O, Cl and F have been replaced by the corresponding isotopes.
The combination of compounds of the preferred embodiments mentioned above with the polymerized compounds described above causes low threshold voltages, low rotational viscosities and very good low-temperature stabilities in the LC media according to the invention at the same time as constantly high clearing points and high HR values, and allows the rapid establishment of a particularly low tilt angle (i.e. a large tilt) in PSA displays. In particular, the LC media exhibit significantly shortened response times, in particular also the grey-shade response times, in PSA displays compared with the LC media from the prior art.
The LC media according to the invention may also comprise further additives which are known to the person skilled in the art and are described in the literature, such as, for example, polymerization initiators, inhibitors, stabilisers, surface-active substances or chiral dopants. These may be polymerizable or non-polymerizable. Polymerizable additives are accordingly ascribed to the polymerizable component or component A). Non-polymerizable additives are accordingly ascribed to the non-polymerizable component or component B).
Furthermore, it is possible to add to the LC media, for example, 0 to 15% by weight of pleochroic dyes, furthermore nanoparticles, conductive salts, preferably ethyldimethyldodecylammonium 4-hexoxybenzoate, tetrabutylammonium tetraphenylborate or complex salts of crown ethers (cf., for example, Haller et al., Mol. Cryst. Liq. Cryst. 24, 249-258 (1973)), for improving the conductivity, or substances for modifying the dielectric anisotropy, the viscosity and/or the alignment of the nematic phases. Substances of this type are described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.
The individual components of the above-listed preferred embodiments of the LC media according to the invention are either known or methods for the preparation thereof can readily be derived from the prior art by the person skilled in the relevant art, since they are based on standard methods described in the literature. Corresponding compounds of the formula CY are described, for example, in EP-A-0 364 538. Corresponding compounds of the formula ZK are described, for example, in DE-A-26 36 684 and DE-A-33 21 373.
The LC media which can be used in accordance with the invention are prepared in a manner conventional per se, for example by mixing one or more of the above-mentioned compounds with one or more polymerizable compounds as defined above, and optionally with further liquid-crystalline compounds and/or additives. In general, the desired amount of the components used in lesser amount is dissolved in the components making up the principal constituent, advantageously at elevated temperature. It is also possible to mix solutions of the components in an organic solvent, for example in acetone, chloroform or methanol, and to remove the solvent again, for example by distillation, after thorough mixing. The invention furthermore relates to the process for the preparation of the LC media according to the invention.
It goes without saying to the person skilled in the art that the LC media according to the invention may also comprise compounds in which, for example, H, N, O, Cl, F have been replaced by the corresponding isotopes like deuterium etc.
The following examples explain the present invention without restricting it. However, they show the person skilled in the art preferred mixture concepts with compounds preferably to be employed and the respective concentrations thereof and combinations thereof with one another. In addition, the examples illustrate which properties and property combinations are accessible.
Preferred mixture components are shown in Table A below.
In Table A, m and n are independently of each other an integer from 1 to 12, preferably 1, 2, 3, 4, 5 or 6, k is 0, 1, 2, 3, 4, 5 or 6, and (O)CmH2m+1 means CmH2m+1 or OCmH2m+1.
In a preferred embodiment of the present invention, the LC media according to the invention comprise one or more compounds selected from the group consisting of compounds from Table A.
Table B shows possible chiral dopants which can be added to the LC media according to the invention.
The LC media preferably comprise 0 to 10% by weight, in particular 0.01 to 5% by weight, particularly preferably 0.1 to 3% by weight, of dopants. The LC media preferably comprise one or more dopants selected from the group consisting of compounds from Table B.
Table C shows possible stabilisers which can be added to the LC media according to the invention. Therein n denotes an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and terminal methyl groups are not shown.
The LC media preferably comprise 0 to 10% by weight, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight, of stabilisers. The LC media preferably comprise one or more stabilisers selected from the group consisting of compounds from Table C.
Table D shows illustrative reactive mesogenic compounds which can be used in the LC media in accordance with the present invention.
In a preferred embodiment, the mixtures according to the invention comprise one or more polymerizable compounds, preferably selected from the polymerizable compounds of the formulae RM-1 to RM-178. Of these, compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-64, RM-74, RM-76, RM-88, RM-102, RM-103, RM-109, RM-117, RM-120, RM-121, RM-122, R-139, RM-142, RM-143, RM-148 to RM-158, RM-164, RM-165 and RM-166 to RM-178 are particularly preferred.
Table E shows self-alignment additives for vertical alignment which can be used in LC media for SA-VA and SA-FFS displays according to the present invention together with the polymerizable compounds of formulae RM-1 to RM-178:
In a preferred embodiment, the LC media, SA-VA and SA-FFS displays according to the present invention comprise one or more SA additives selected from formulae SA-1 to SA-48, preferably from formulae SA-14 to SA-48, very preferably from formulae SA-20 to SA-34 and SA-44, in combination with one or more RMs of formulae RM-1 to RM-178.
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.
In the foregoing and in the examples, all temperatures are set forth uncorrected in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.
The entire disclosures of all applications, patents and publications, cited herein and of corresponding European Application No. 21213602.2, filed Dec. 10, 2021, are incorporated by reference herein.
The following examples explain the present invention without restricting it. However, they show the person skilled in the art preferred mixture concepts with compounds preferably to be employed and the respective concentrations thereof and combinations thereof with one another. In addition, the examples illustrate which properties and property combinations are accessible.
In addition, the following abbreviations and symbols are used:
Unless explicitly noted otherwise, all concentrations in the present application are quoted in per cent by weight and relate to the corresponding mixture as a whole, comprising all solid or liquid-crystalline components, without solvents.
Unless explicitly noted otherwise, all temperature values indicated in the present application, such as, for example, for the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I), are quoted in degrees Celsius (°C). M.p. denotes melting point, cl.p. = clearing point. Furthermore, C = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols represent the transition temperatures.
All physical properties are and have been 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., and Δn is determined at 589 nm and Δε at 1 kHz, unless explicitly indicated otherwise in each case.
The term “threshold voltage” for the present invention relates to the capacitive threshold (V0), also known as the Freedericks threshold, unless explicitly indicated otherwise. In the examples, the optical threshold may also, as generally usual, be quoted for 10% relative contrast (V10).
Unless stated otherwise, the process of polymerizing the polymerizable compounds in the PSA displays as described above and below is carried out at a temperature where the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably is carried out at room temperature.
Unless stated otherwise, methods of preparing test cells and measuring their electrooptical and other properties are carried out by the methods as described hereinafter or in analogy thereto.
The display used for measurement of the capacitive threshold voltage usually consists of two plane-parallel glass outer plates at a separation of 25 µm, each of which has on the inside an electrode layer and an unrubbed polyimide alignment layer on top, which effect a homeotropic edge alignment of the liquid-crystal molecules.
The PSVA display or PSVA test cell used for measurement of the tilt angles usually consists of two plane-parallel glass outer plates at a separation of ca. 4 pm unless stated otherwise, each of which has on the inside an electrode layer and a polyimide alignment layer on top, where the two polyimide layers are rubbed antiparallel to one another and effect a homeotropic edge alignment of the liquid-crystal molecules. The SAVA display or test cell has the same structure but wherein one or both polyimide layers are omitted.
The polymerizable compounds are usually polymerized in the display or test cell by irradiation with UV light of defined intensity for a prespecified time, with a voltage simultaneously being applied to the display (usually 10 V to 30 V alternating current, 1 kHz).
The intensity is measured using a standard meter (Hoenle UV-meter high end with UV sensor).
The tilt angle is usually determined using the Mueller Matrix Polarimeter “AxoScan” from Axometrics. A low value (i.e. a large deviation from the 90° angle) corresponds to a large tilt here.
Unless stated otherwise, the term “tilt angle” means the angle between the LC director and the substrate, and “LC director” means in a layer of LC molecules with uniform orientation the preferred orientation direction of the optical main axis of the LC molecules, which corresponds, in case of calamitic, uniaxially positive birefringent LC molecules, to their molecular long axis.
The nematic LC host mixture N1 is formulated as follows
Polymerizable mixtures P11 to P13 according to the present invention are prepared by adding polymerizable compound MA1 of formula IA1 and polymerizable compound MB1 of formula IBD1 to nematic LC host mixture N1 in varying concentrations.
For comparison purpose polymerizable mixture C11 is prepared by adding only 0.3% of polymerizable compound MA1 of formula IA6 to nematic LC host mixture N1.
The polymerizable mixture compositions are shown in Table 1.1.
Each polymerizable mixture further contains 150 ppm of the stabilizer S1-1 and 10 ppm of Irganox®1076.
Tilt Angle Generation
Electrooptical VA test cells with AF glass substrates containing the polymerizable mixtures are exposed to UV light in a two step process, the first step (UV1) for generating a tilt angle and the second step (UV2) for polymerizing any residual monomer that was not polymerized in the first step. In UV1 step a voltage is applied (0.1 V step and curing at DC 15V). In UV2 step no voltage is applied. As radiation source a fluorescent UV lamp type C with a cut-off filter of 313 nm was used. The UV intensity is checked by UV detector with 313 nm. The other conditions are as follows, unless stated otherwise:
UV1 (C-type lamp): 0.22 mW/cm2 at room temperature for 30-200 s UV2 (C-type lamp): 0.32 mW/cm2 at RT, 120 min
The tilt angle generated in the test cells after the UV1 step above after varying irradiation times is measured using an Otsuka T_RETS-10 system. The results are shown in Table 1.2.
It can be seen that polymerizable mixtures P11 to P13 according to the invention show a significantly faster tilt angle generation than reference mixture C11.
Tilt stability, i.e. the change of the tilt angle after repeated electric stress, is a criterion for evaluating the risk of image sticking. A low value for the change of the tilt angle indicates a good tilt stability and a low potential risk of image sticking.
For determining the tilt stabillity the test cells after polymerization as described above for the tilt angle generation are electrically stressed with a square wave of 40 VPP at 60 Hz for 168 h on backlight unit. After a relaxation time of 5-10 min the tilt angles are measured using the Otsuka T_RETS-10 system.
The change of the tilt angle Δtilt is determined according to equation (1)
The lower the value of Δtilt, the higher is the tilt stability.
The results are shown in Table 1.3.
It can be seen that polymerizable mixtures P11 to P13 according to the invention show better tilt stability than reference mixture C11.
The residual content of unpolymerized monomer (in ppm) in the mixture was determined after UV photopolymerization. The smaller the residual monomer content after a given time interval, the faster the polymerization. For this purpose the polymerizable mixtures were filled in test cells and polymerized by UV exposure for varying time intervals at RT using a fluorescent UV lamp type C with an intensity of 0.32 mW/cm2 The UV intensity is checked by UV detector with 313 nm. After photopolymerization for a certain time interval the test cells were opened, and the mixture was dissolved and rinsed out of the test cell with methyl ethyl ketone and analyzed by Ultra Performance Liquid Chromatography (UPLC).
The results are shown in Table 1.4.
It can be seen that the total residual content of all monomers after polymerization in the polymerizable mixtures P11 to P13 according to the invention is smaller than in the polymerizable reference mixture C11. This is especially surprising when considering that the initial amount of monomers in mixtures P11 to P13 was twice as high as in reference mixture C11.
For the VHR measurement the polymerizable LC media were filled in in test cells with a fishbone pattern ITO electrode and the monomers were polymerized under the same conditions as described above for the tilt angle generation. The VHR was measured before and after UV exposure while applying a voltage of 1 V / 0.6 Hz at 60° C.
Light stress usually causes the decrease of VHR in LC mixtures, therefore the smaller the absolute decrease of VHR value after stress, the better performance for display applications.
The results are shown in Table 1.5.
It can be seen that the VHR of polymerizable mixtures P11 to P13 according to the invention after UV stress is at similar level to that polymerizable mixture C11, especially when considering that the total amount of monomers in mixtures P11 to P13 is twice as high as in reference mixture C11.
Overall, the above results demonstrate that the polymerizable mixtures comprising both a polymerizable compound of formula IA and of formula IB show significant improvements like better tilt stability and lower amount of residual monomer.
The nematic LC host mixture N2 is formulated as follows
Polymerizable mixtures P21 to P23 according to the present invention are prepared by adding polymerizable compound MA1 of formula IA6 and polymerizable compound MB1 of formula IBD1 to nematic LC host mixture N2 in varying concentrations.
The polymerizable mixture compositions are shown in Table 2.1.
Each polymerizable mixture further contains 150 ppm of the stabilizer S1-1 and 10 ppm of lrganox®1076.
The tilt stability is determined as described in Example 1. The results are shown in Table 2.2.
It can be seen that polymerizable mixtures P21 to P23 according to the invention show good tilt stability.
The residual content of unpolymerized monomer is measured as described in Example 1. The results are shown in Table 2.3.
It can be seen that the polymerizable mixtures P21 to P23 according to the invention show quick and complete polymerization with a low residual content of unreacted monomers at proper UV exposure time .
The VHR of the polymerizable LC media is measured as described in Example 1. The results are shown in Table 2.4.
It can be seen that the VHR of polymerizable mixtures P21 to P23 according to the invention after UV stress is still high, and there is only a low drop of the VHR, especially in mixtures P21 and P23 with higher content of monomer M1.
Overall, the above results demonstrate that the polymerizable mixtures comprising both a polymerizable compound of formula IA and of formula IB show significant improvements like better tilt angle generation, higher tilt stability and lower amount of residual monomer.
Polymerizable mixtures P31 and P32 according to the present invention are prepared by adding polymerizable compound MA1 of formula IA6, polymerizable compound MB1 of formula IBD1 and polymerizable compound MC1 of formula IC45 to nematic LC host mixture N2 in varying concentrations.
The polymerizable mixture compositions are shown in Table 3.1.
Each polymerizable mixture further contains 150 ppm of the stabilizer S1-1 and 10 ppm of lrganox®1076.
The tilt stability is determined as described in Example 1. The results are shown in Table 3.2.
It can be seen that polymerizable mixtures P31 and P32 according to the invention show good tilt stability.
The residual content of unpolymerized monomer is measured as described in Example 1. The results are shown in Table 3.3.
It can be seen that the polymerizable mixtures P31 and P32 according to the invention show quick and complete polymerization with a low residual content of unreacted monomers at proper UV exposure time .
The VHR of the polymerizable LC media is measured as described in Example 1. The results are shown in Table 3.4.
It can be seen that the VHR of polymerizable mixtures P31 and P32 according to the invention after UV stress is still high, and there is only a low drop of the VHR.
Overall, the above results demonstrate that the polymerizable mixtures comprising both a polymerizable compound of formula IA and of formula IB show significant improvements like better tilt stability and lower amount of residual monomer.
The nematic LC host mixture N3 is formulated as follows
Polymerizable mixture P4 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of lrganox®1076 to 99.434% of the nematic LC host mixture N3.
Polymerizable mixture P5 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB1 and 100 ppm of the stabilizer S1-1 to 99.49% of the nematic LC host mixture N3.
The nematic LC host mixture N4 is formulated as follows
Polymerizable mixture P6 is prepared by adding 0.2% of compound MA1 and 0.2% of compound MB1 to 99.6% of the nematic LC host mixture N4.
Polymerizable mixture P7 is prepared by adding 0.2% of compound MA1, 0.25% of compound MB1, 0.05% of compound MC1, 100 ppm of stabilizer S1-1 and 10 ppm of lrganox®1076 to 99.539% of the nematic LC host mixture N4.
The nematic LC host mixture N5 is formulated as follows
Polymerizable mixture P8 is prepared by adding 0.2% of compound MA1 and 0.1% of compound MC1 to the nematic LC host mixture N5.
Polymerizable mixture P9 is prepared by adding 0.2% of compound MA1, 0.2% of compound MB1 and 50 ppm of the stabilizer S1-1 to the nematic LC host mixture N8.
The nematic LC host mixture N6 is formulated as follows
Polymerizable mixture P10 is prepared by adding 0.1% of compound MA1 and 0.3% of compound MB1 to the nematic LC host mixture N6.
Polymerizable mixture P11 is prepared by adding 0.1% of compound MA1, 0.3% of compound MB1, 0.1% of compound MC1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N6.
Polymerizable mixture P12 is prepared by adding 0.2% of compound MA1 and 0.2% of compound MC1 to the nematic LC host mixture N1.
Polymerizable mixture P13 is prepared by adding 0.2% of compound MA1, 0.2% of compound MB1, 0.1% of compound MC1 and and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P14 is prepared by adding 0.1% of the compound MA2 of formula IA1 and 0.3% of compound MB1 to the nematic LC host mixture N1.
Polymerizable mixture P15 is prepared by adding 0.1% of compound MA2, 0.3% of compound MB1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N2.
Polymerizable mixture P16 is prepared by adding 0.2% of compound MA2, 0.1% of compound MC1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P17 is prepared by adding 0.2% of compound MA2, 0.1% of compound MB1, 0.05% of compound MC1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P18 is prepared by adding 0.1% of compound MA1, 0.3% of compound M5 of formula IBD4 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P19 is prepared by adding 0.1% of compound MA2, 0.3% of compound MB2 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N2.
Polymerizable mixture P20 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB2, 0.2% of compound MC1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P21 is prepared by adding 0.1% of compound MA1, 0.3% of compound MB3 of formula IBT1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P22 is prepared by adding 0.2% of compound MA1, 0.1% of compound MC1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P23 is prepared by adding 0.1% of compound MA2, 0.3% of compound MB3 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N2.
Polymerizable mixture P24 is prepared by adding 0.1% of compound MA1, 0.3% of the compound MB4 of formula IBT22 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P25 is prepared by adding 0.2% of compound MA2, 0.2% of compound MB4 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P26 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB4, 0.05% of compound MC1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P27 is prepared by adding 0.1% of compound MA1, 0.3% of compound MB5 of formula IBT35 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P28 is prepared by adding 0.2% of compound MA1, 0.2% of compound MB5, 0.05% of compound MC1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P29 is prepared by adding 0.1% of compound MA2, 0.3% of compound MB5 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N2.
The nematic LC host mixture N7 is formulated as follows
Polymerizable mixture P30 is prepared by adding 0.35% of compound MA1, 0.15% of compound MB1 and 50 ppm of the stabilizer S1-1 to the nematic LC host mixture N6.
The nematic LC host mixture N8 is formulated as follows
Polymerizable mixture P31 is prepared by adding 0.2% of compound MA1, 0.2% of compound MB1 and 50 ppm of the stabilizer S2-1 to the nematic LC host mixture N8.
The nematic LC host mixture N9 is formulated as follows
Polymerizable mixture P32 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N9.
The nematic LC host mixture N10 is formulated as follows
Polymerizable mixture P33 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB1 and 0.6% of the SA additive SA23 to the nematic LC host mixture N10.
The nematic LC host mixture N11 is formulated as follows
Polymerizable mixture P34 is prepared by adding 0.1% of compound MA2, 0.2% of compound MB1, 0.05% of compound MC1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N11.
The nematic LC host mixture N12 is formulated as follows
Polymerizable mixture P35 is prepared by adding 0.2% of compound MA1, 0.2% of compound MB1 and 150 ppm of the stabilizer S2-1 to the nematic LC host mixture N12.
The nematic LC host mixture N13 is formulated as follows
Polymerizable mixture P36 is prepared by adding 0.1% of compound MA1, 0.3% of compound MB1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N13.
The nematic LC host mixture N14 is formulated as follows
Polymerizable mixture P37 is prepared by adding 0.3% of compound MA1, 0.1% of compound MB1 and 50 ppm of the stabilizer S1-1 to the nematic LC host mixture N14.
The nematic LC host mixture N15 is formulated as follows
Polymerizable mixture P38 is prepared by adding 0.4% of compound MA1, 0.1% of compound MB1 and 50 ppm of the stabilizer S2-1 to the nematic LC host mixture N15.
The nematic LC host mixture N16 is formulated as follows
Polymerizable mixture P39 is prepared by adding 0.3% of compound MA2, 0.2% of compound MB1 and 150 ppm of the stabilizer S3-1 to the nematic LC host mixture N16.
The nematic LC host mixture N17 is formulated as follows
Polymerizable mixture P40 is prepared by adding 0.25% of compound MA1, 0.1% of compound MB1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N17.
The nematic LC host mixture N18 is formulated as follows
Polymerizable mixture P41 is prepared by adding 0.15% of compound MA2, 0.2% of compound MB3 and 100 ppm of the stabilizer S3-2 to the nematic LC host mixture N18.
The nematic LC host mixture N19 is formulated as follows
Polymerizable mixture P42 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB3 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N19.
The nematic LC host mixture N20 is formulated as follows
Polymerizable mixture P43 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N20.
The nematic LC host mixture N21 is formulated as follows
Polymerizable mixture P44 is prepared by adding 0.15% of compound MA1, 0.2% of compound MB1, 0.05% of compound MC1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N21.
The nematic LC host mixture N22 is formulated as follows
Polymerizable mixture P45 is prepared by adding 0.2% of compound 1, 0.25% of compound MB1, 0.05% of compound MC1 and 50 ppm of the stabilizer S1-1 to the nematic LC host mixture N22.
The nematic LC host mixture N23 is formulated as follows
Polymerizable mixture P46 is prepared by adding 0.3% of compound MA1, 0.3% of compound MB1 and 0.6% of the SA additive SA32 to the nematic LC host mixture N23.
The nematic LC host mixture N24 is formulated as follows
Polymerizable mixture P47 is prepared by adding 0.25% of compound MA1, 0.15% of compound MB1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N24.
The nematic LC host mixture N25 is formulated as follows
Polymerizable mixture P48 is prepared by adding 0.1% of compound MA1, 0.3% of compound MB1 and 100 ppm of the stabilizer S2-1 to the nematic LC host mixture N25.
The nematic LC host mixture N26 is formulated as follows
Polymerizable mixture P49 is prepared by adding 0.2% of compound MA1, 0.05% of the compond MC1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N26.
The nematic LC host mixture N27 is formulated as follows
Polymerizable mixture P50 is prepared by adding 0.3% of compound MA2, 0.2% of compound MB1 and 50 ppm of the stabilizer S3-1 to the nematic LC host mixture N27.
The nematic LC host mixture N28 is formulated as follows
Polymerizable mixture P51 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB2 and 50 ppm of the stabilizer S3-3 to the nematic LC host mixture N28.
The nematic LC host mixture N29 is formulated as follows
Polymerizable mixture P52 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB4 and 150 ppm of the stabilizer S2-1 to the nematic LC host mixture N29.
The nematic LC host mixture N30 is formulated as follows
Polymerizable mixture P53 is prepared by adding 0.2% of compound MA2, 0.1% of compound MB1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N30.
The nematic LC host mixture N31 is formulated as follows
Polymerizable mixture P54 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB5 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N31.
The nematic LC host mixture N32 is formulated as follows
Polymerizable mixture P55 is prepared by adding 0.3% of compound MA2, 0.4% of compound MB4 and 0.6% of the SA additive SA23 to the nematic LC host mixture N32.
The nematic LC host mixture N33 is formulated as follows
Polymerizable mixture P56 is prepared by adding 0.4% of compound MA1, 0.2% of compound MB1, 0.6% of the SA additive SA23 and 50 ppm of the stabilizer S3-3 to the nematic LC host mixture N33.
The nematic LC host mixture N34 is formulated as follows
Polymerizable mixture P57 is prepared by adding 0.4% of compound MA2, 0.2% of compound MB1, 0.6% of the SA additive SA32 and 50 ppm of the stabilizer S3-1 to the nematic LC host mixture N34.
The nematic LC host mixture N35 is formulated as follows
Polymerizable mixture P58 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB5, 0.1% of compound MC1 and 150 ppm of the stabilizer S3-2 to the nematic LC host mixture N35.
The nematic LC host mixture N36 is formulated as follows
Polymerizable mixture P59 is prepared by adding 0.2% of compound MA2, 0.3% of compound MB2, 0.05% of compound MC1 and 150 ppm of the stabilizer S3-3 to the nematic LC host mixture N36.
The nematic LC host mixture N37 is formulated as follows
Polymerizable mixture P60 is prepared by adding 0.3% of compound MA1, 0.3% of compound MB1, 0.6% of the SA additive SA23 and 50 ppm of the stabilizer S1-1 to the nematic LC host mixture N37.
The nematic LC host mixture N38 is formulated as follows
Polymerizable mixture P61 is prepared by adding 0.2% of compound MA2, 0.3% of compound MB3, 0.1% of compound MC1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N38.
The nematic LC host mixture N39 is formulated as follows
Polymerizable mixture P62 is prepared by adding 0.2% of compound MA1, 0.2% of compound MB4, 0.1% of compound MC1 and 150 ppm of the stabilizer S3-3 to the nematic LC host mixture N39.
The nematic LC host mixture N40 is formulated as follows
Polymerizable mixture P63 is prepared by adding 0.2% of compound MA1, 0.1% of compound MC1 and 150 ppm of the stabilizer S3-2 to the nematic LC host mixture N40.
The nematic LC host mixture N41 is formulated as follows
Polymerizable mixture P64 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB1, 0.1% of the commpond MC1 and 100 ppm of the stabilizer S3-3 to the nematic LC host mixture N41.
The nematic LC host mixture N42 is formulated as follows
Polymerizable mixture P65 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB1, 0.1% of compound MC1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N42.
The nematic LC host mixture N43 is formulated as follows
Polymerizable mixture P66 is prepared by adding 0.4% of compound MA1, 0.2% of compound MB1 and 150 ppm of the stabilizer S2-1 to the nematic LC host mixture N43.
The nematic LC host mixture N44 is formulated as follows
Polymerizable mixture P67 is prepared by adding 0.2% of compound MA2, 0.3% of compound MB2 and 150 ppm of the stabilizer S3-2 to the nematic LC host mixture N44.
The nematic LC host mixture N45 is formulated as follows
Polymerizable mixture P68 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB3, 0.05% of compound MC1 and 150 ppm of the stabilizer S3-3 to the nematic LC host mixture N45.
The nematic LC host mixture N46 is formulated as follows
Polymerizable mixture P69 is prepared by adding 0.4% of compound MA1, 0.2% of compound MB1, 0.6% of the SA additive SA32 and 50 ppm of the stabilizer S3-1 to the nematic LC host mixture N46.
The nematic LC host mixture N47 is formulated as follows
Polymerizable mixture P70 is prepared by adding 0.3% of compound MA1, 0.2% of compound MB1, 0.6% of the SA additive SA32 and 50 ppm of the stabilizer S2-1 to the nematic LC host mixture N47.
The nematic LC host mixture N48 is formulated as follows
Polymerizable mixture P71 is prepared by adding 0.4% of compound MA1, 0.3% of compound MB1, 0.6% of the SA additive SA32 and 50 ppm of the stabilizer S3-3 to the nematic LC host mixture N48.
The nematic LC host mixture N49 is formulated as follows
Polymerizable mixture P72 is prepared by adding 0.2% of compound MA1 and 0.2% of compound MB1 to the nematic LC host mixture N49.
Polymerizable mixture P73 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC2 of formula IC1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P74 is prepared by adding 0.1% of compound MA1, 0.3% of compound MB2, 0.05% of compound MC2 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P75 is prepared by adding 0.2% of compound MA2, 0.1% of compound MC2 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P76 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of the compound MC3 of formula IC13 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P77 is prepared by adding 0.2% of compound MA2, 0.2% of compound MB2, 0.1% of compound MC2 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P76 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of the compound MC4 of formula IC22 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P79 is prepared by adding 0.2% of compound MA1, 0.1% of the compound MC5 of formula IC23 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P80 is prepared by adding 0.1% of compound MA2, 0.3% of compound MB2, 0.05% of compound MC5 and 100 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P81 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of the compound MC6 of formula IC25 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
Polymerizable mixture P82 is prepared by adding 0.2% of compound MA2, 0.2% of compound MB4, 0.05% of compound MC6 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N1.
Polymerizable mixture P83 is prepared by adding 0.2% of compound MA1, 0.1% of compound MC6 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N3.
The nematic LC host mixture N50 is formulated as follows
Polymerizable mixture P84 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.484% of the nematic LC host mixture N50.
The nematic LC host mixture N51 is formulated as follows
Polymerizable mixture P85 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.484% of the nematic LC host mixture N51.
The nematic LC host mixture N52 is formulated as follows
Polymerizable mixture P86 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.434% of the nematic LC host mixture N52.
The nematic LC host mixture N53 is formulated as follows
Polymerizable mixture P87 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.434% of the nematic LC host mixture N53.
The nematic LC host mixture N54 is formulated as follows
Polymerizable mixture P88 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.434% of the nematic LC host mixture N54.
Polymerizable mixture P89 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.484% of the nematic LC host mixture N54.
The nematic LC host mixture N55 is formulated as follows
Polymerizable mixture P90 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.484% of the nematic LC host mixture N55.
Polymerizable mixture P91 is prepared by adding 0.94% of the chiral dopant S-4011 to 99.06% of the polymerizable mixture P90.
The nematic LC host mixture N56 is formulated as follows
Polymerizable mixture P92 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.434% of the nematic LC host mixture N56.
Polymerizable mixture P93 is prepared by adding 0.89% of the chiral dopant S-4011 to 99.11% of the polymerizable mixture P92.
The nematic LC host mixture N57 is formulated as follows
Polymerizable mixture P94 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.434% of the nematic LC host mixture N57.
Polymerizable mixture P95 is prepared by adding 0.91% of the chiral dopant S-4011 to 99.09% of the polymerizable mixture P94.
The nematic LC host mixture N58 is formulated as follows
Polymerizable mixture P96 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.484% of the nematic LC host mixture N58.
The nematic LC host mixture N59 is formulated as follows
Polymerizable mixture P97 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.434% of the nematic LC host mixture N59.
The nematic LC host mixture N60 is formulated as follows
Polymerizable mixture P98 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.434% of the nematic LC host mixture N60.
The nematic LC host mixture N61 is formulated as follows
Polymerizable mixture P99 is prepared by adding 0.2% of compound MA1, 0.3% of compound MB1, 0.05% of compound MC1, 150 ppm of the stabilizer S1-1 and 10 ppm of the stabilizer Irganox®1076 to 99.434% of the nematic LC host mixture N61.
Polymerizable mixture P100 is prepared by adding 0.92% of the chiral dopant S-4011 to 99.08% of the polymerizable mixture P99.
The nematic LC host mixture N62 is formulated as follows
Polymerizable mixture P101 is prepared by adding 0.2% of compound MA1, 0.4% of compound MB1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N62.
The nematic LC host mixture N63 is formulated as follows
Polymerizable mixture P102 is prepared by adding 0.2% of compound MA1, 0.4% of compound MB1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N63.
The nematic LC host mixture N64 is formulated as follows
Polymerizable mixture P103 is prepared by adding 0.2% of compound MA1, 0.4% of compound MB1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N64.
The nematic LC host mixture N65 is formulated as follows
Polymerizable mixture P104 is prepared by adding 0.2% of compound MA1, 0.4% of compound MB1 and 150 ppm of the stabilizer S1-1 to the nematic LC host mixture N65.
The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21213602.2 | Dec 2021 | EP | regional |
