Abstract: The invention relates to a liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy, which contains at least one compound of the formula I and at least one compound of the formula II in which R1, R2, R3, R4, ring A, Z1, Z2 and m are as defined in claim 1, and to the use thereof for an active-matrix display based on the ECB, VA, PS-VA, FFS, PALC or IPS effect.

Abstract: The invention provides a liquid crystal compound that has an excellent compatibility with other liquid crystal compounds and also has at least one of characteristics such as a high stability to heat, light or the like, a suitable refractive index anisotropy (?n), a low threshold voltage and a suitable dielectric anisotropy (??). A compound represented by formula (1). For example, R1 is alkyl having 1 to 10 carbons, R2 is halogen or alkenyl having 2 to 10 carbons; the ring A1, the ring A2 and the ring A3 are 1,4-cyclohexylene or 1,4-phenylene; Z1, Z2 and Z3 are a single bond or alkylene having 1 to 4 carbons; G is —CH2— or —O—; and m is 1, and n and p is 0 or 1.

Abstract: A liquid crystal composition is described, which has a nematic phase, contains a specific compound having a high maximum temperature or a large dielectric anisotropy as a first component and a specific compound having a large dielectric anisotropy as a second component, and may also contain a specific compound having a high maximum temperature or a small viscosity as a third component and a specific compound having a high maximum temperature or a large dielectric anisotropy as a fourth component. An active-matrix (AM) liquid crystal display device including the liquid crystal composition is also described.

Abstract: The instant invention relates to mesogenic media exhibiting a blue phase, comprising one, two or more compounds of formula I-A wherein the parameters are as specified in the text, preferably stabilised by a polymer, and their use in electro-optical light modulation elements and their respective use in displays, as well as to such displays.

Abstract: Disclosed herein are an epoxy resin composition for a printed circuit board, an insulating film, a prepreg, and a multilayer printed circuit board, the epoxy resin composition for a printed circuit board including a liquid crystal oligomer, an epoxy resin, an amino triazine novolac hardener, and an inorganic filler; the insulating film and the prepreg each being manufactured by using the resin composition; and the multilayer printed circuit board including the insulating film or the prepreg.

Abstract: The invention relates to compounds of the formula I in which R0, A0, A1, A2, Z0, Z1, Z2, L1, L2, X, l, m and n have the meanings indicated in claim 1, and to the use thereof in liquid-crystalline media, and to liquid-crystalline media comprising one or more compounds of the formula I in electro-optical liquid-crystal displays.

Abstract: Providing a liquid crystal composition satisfies at least one of characteristics like a high maximum temperature of a nematic phase, a low minimum temperature of the nematic phase, a small viscosity, a suitable optical anisotropy, a large negative dielectric anisotropy, a large specific resistance, a high stability to ultraviolet light and a high stability to heat. Providing a liquid crystal composition has a suitable balance regarding at least two of the characteristics. Providing an AM device has a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth. The liquid crystal composition has a negative dielectric anisotropy and contains a specific compound having a large negative dielectric anisotropy as a first component and a specific three-ring compound having a large optical anisotropy and a negative dielectric anisotropy as a second component, and a liquid crystal display device contains the composition.

Abstract: The invention relates to liquid-crystalline compounds of the formula I in which R1, R2, A1, A2, A3, A4, Z1, Z2, Z3, V, a, b and c have the meanings indicated in Claim 1, and to liquid-crystalline media comprising at least one compound of the formula I, and to electro-optical displays containing a liquid-crystalline medium of this type.

Abstract: The invention relates to a liquid-crystalline medium comprising at least one compound of the formula I, in which R1 has the meanings indicated in claim 1, and to the use thereof in liquid-crystalline media and in electro-optical liquid-crystal displays.

Abstract: Disclosed is a liquid crystal composition formed by including a polymerizable compound represented by general formula (I) in a nematic liquid crystal composition with negative dielectric anisotropy (??). In the formula, ring C1 represents a benzene-1,2,4-triyl group, or the like; rings C2 to C4 represent a 1,4-phenylene group, a naphthalene-2,6-diyl group, or the like; M1 to M3 represent a hydrogen atom or a methyl group; Z1 and Z2 are a direct coupling, -L1-, -L1O—, -L1O—CO—, or the like; Z6 is a direct coupling, -L2-, -OL2-, —O—COL2-, or the like; at least one of Z1, Z2, and Z6 is not a direct coupling; L1 and L2 represent a C1-10 alkylene group; Z3 to Z5 represent a direct coupling, an ester bond, or the like; and p, q, and r are 0 or 1, wherein 1?p+q+r?3.

Abstract: The invention provides a liquid crystal compound that has an excellent compatibility with other liquid crystal compounds and also has at least one of characteristics such as a high stability to heat, light or the like, a suitable refractive index anisotropy (?n), a low threshold voltage and a suitable dielectric anisotropy (??). A compound represented by formula (1). For example, R1 is alkyl having 1 to 10 carbons, R2 is halogen or alkenyl having 2 to 10 carbons; the ring A1, the ring A2 and the ring A3 are 1,4-cyclohexylene or 1,4-phenylene; Z1, Z2 and Z3 are a single bond or alkylene having 1 to 4 carbons; G is —CH2— or —O—; and m is 1, and n and p is 0 or 1.

Abstract: The instant invention relates to mesogenic media exhibiting a blue phase, comprising two or more components selected from the following components, components A to C, component A comprising one or more compounds selected from the group of compounds of formula I-T component B consisting of one or more compounds selected from the group of compounds of formula I-N component C consisting of one or more compounds selected from the group of compounds of formula I-E wherein the parameters are as specified in the text, preferably stabilized by a polymer, and their use in electro-optical light modulation elements and their respective use in displays, as well as to such displays.

Abstract: To provide a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature of a nematic phase, low minimum temperature thereof, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy and specific resistance, high stability to ultraviolet light and heat; a liquid crystal composition having a suitable balance regarding at least two thereof; and an AM device having short response time, large voltage holding ratio and contrast ratio, long life and so forth. The liquid crystal composition has nematic phase, and contains as a first component a specific compound having large dielectric anisotropy and as a second component a specific compound having small viscosity, and may contain as a third component a specific compound having high maximum temperature or large dielectric anisotropy, and as a fourth component a specific compound having high maximum temperature or small viscosity, and a liquid crystal display device includes the composition.

Abstract: A novel liquid crystalline carbonate and the mixture containing the same: wherein R3 is an alkyl (H2n+1Cn) or an alkenyl (H2n?1Cn) group, each of 1 to 12 carbon atoms, the ring A is laterally unsubstituted benzene or pyridine or pyrimidine or trans-substituted cyclohexane ring, symbol r is 0 to 2; the lateral substituents: X2, X3, X4 and X5 in the benzene rings represent independently hydrogen or fluorine or chlorine atoms, X1 is hydrogen or fluorine atom and simultaneously at least one of the substituents: X2, X3 and X4 is fluorine or chlorine atoms, Y is an alkyl or an alkyloxy or an alkenyl or an alkenyloxy group, each of 1 to 12 carbon atoms or hydrogen or fluorine or chlorine atom or NCS group are described.

Abstract: A liquid crystal composition that satisfies at least one of characteristics such as a high maximum temperature of a nematic phase, a low minimum temperature of a nematic phase, a small viscosity, a suitable optical anisotropy, a large negative dielectric anisotropy, a large specific resistance, a high stability to ultraviolet light and a high stability to heat or that is suitably balanced between at least two of the characteristics, is described. The liquid crystal composition includes a compound having three or more polymerizable groups as a first component and a compound having one or two polymerizable groups as a second component in a suitable ratio, and that may include a specific compound having a large negative dielectric anisotropy and a low minimum temperature as a third component or a specific compound having a small viscosity or a high maximum temperature as a fourth component.

Abstract: To provide a liquid crystal composition satisfying at least one of characteristics such as a high maximum temperature of a nematic phase, a low minimum temperature of the nematic phase, small viscosity, suitable optical anisotropy, large dielectric anisotropy, large specific resistance, high stability to ultraviolet light, high stability to heat and a large elastic constant, or is to provide a liquid crystal composition having a suitable balance regarding at least two of the characteristics; an AM device having short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth. The liquid crystal composition has the nematic phase and contains a compound having a difluoromethyleneoxy group and a trifluoromethyl group and having large dielectric anisotropy as a first component, and a specific compound having small dielectric anisotropy as a second component. The liquid crystal display device contains the composition.

Abstract: To provide a liquid crystal compound having a high stability to light, a high clearing point, a low minimum temperature of a liquid crystal phase, a small viscosity, a suitable optical anisotropy, a large dielectric anisotropy, a suitable elastic constant and an excellent solubility in other liquid crystal compounds.

Abstract: Provided is an AM device containing a liquid crystal composition satisfying at least one of characteristics such as a high maximum temperature of a nematic phase, a low minimum temperature of the nematic phase, a small viscosity, a large optical anisotropy, a large positive dielectric anisotropy, a large specific resistance, a high stability to ultraviolet light and a high stability to and heat, or having a suitable balance regarding at least two of the characteristics, and the AM device having a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth; wherein a liquid crystal display device contains a liquid crystal composition having a positive dielectric anisotropy and containing a specific compound having a large positive dielectric anisotropy as a first component and a specific compound having a small viscosity as a second component.

Abstract: To provide a liquid crystal composition satisfying at least one characteristic such as high maximum temperature of nematic phase, low minimum temperature thereof, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy and specific resistance, high stability to ultraviolet light and heat; a liquid crystal composition having a suitable balance regarding at least two thereof; and an AM device including the composition.

Abstract: The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I, in which R1, R1*, rings A and B, Z1, L1, L2, a and b have the meanings indicated in Claim 1, and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, IPS or PS-IPS effect.

Abstract: Providing a liquid crystal composition satisfying at least one of characteristics such as high maximum temperature of nematic phase, low minimum temperature of the nematic phase, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light and heat, or having a suitable balance regarding at least two of the characteristics; and an AM device having short response time, large voltage holding ratio, large contrast ratio, long service life and so forth. The liquid crystal composition has a negative dielectric anisotropy and contains a specific two-ring compound having a low minimum temperature as a first component, a specific compound having a large negative dielectric anisotropy as a second component, a specific compound having a low viscosity as a third component, and a specific compound having a large negative dielectric anisotropy as a fourth component. The liquid crystal display device contains the composition.

Abstract: Disclosed are liquid-crystal (LC) media for use in LC displays of the PS (polymer stabilised) or PSA (polymer sustained alignment) type which contain a liquid-crystal (LC) mixture that contains one or more compounds of formula I

Abstract: The invention is to provide a liquid crystal compound having a large dielectric anisotropy, a high voltage holding ratio and stability to heat, light and so forth, maintaining a nematic phase in a wide temperature range, having a suitable optical anisotropy and an excellent compatibility with other liquid crystal compounds, particularly, to provide a liquid crystal compound having a large dielectric anisotropy. The invention provides compound (1): In the formula, for example, R1 is alkyl having 1 to 20 carbons; ring A1, ring A2, ring A3, ring A4, ring A5 and ring A6 are independently 1,4-cyclohexylene or 1,4-phenylene; Z1, Z2, Z3, Z4, Z5, Z6 and Z7 are independently a single bond, —(CH2)2—, —COO—, —OCO—, —CF2O—, —OCF2— or —CH?CH—; X1 is fluorine, —CF3 or —OCF3; and Y1 and Y2 are independently hydrogen or fluorine.

Abstract: A liquid crystal compound having a high stability to heat, light and so forth, a high clearing point, a low minimum temperature of a liquid crystal phase, a small viscosity, a suitable optical anisotropy, a large dielectric anisotropy, a suitable elastic constant and an excellent solubility in other liquid crystal compounds, a liquid crystal composition containing the compound, and a liquid crystal display device including the composition. The compound is represented by formula (1): wherein, for example, R1 is fluorine or alkyl having 1 to 10 carbons; ring A1 and ring A2 are 1,4-phenylene, or 1,4-phenylene in which at least one of hydrogen is replaced by fluorine; Z1, Z2 and Z3 are a single bond; L1 and L2 are hydrogen or fluorine; X1 is fluorine or —CF3; and m is 1, and n is 0.

Abstract: Providing a liquid crystal composition satisfies at least one of characteristics like high maximum temperature of a nematic phase, low minimum temperature of the nematic phase, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to ultraviolet light and high stability to heat or has a suitable balance regarding at least two of the characteristics. Providing an AM device has a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth. The liquid crystal composition has a negative dielectric anisotropy and contains a specific compound having large negative dielectric anisotropy as a first component, a specific two-ring compound having low minimum temperature and negative dielectric anisotropy as a second component and a specific two-ring compound having low viscosity as a third component. The liquid crystal display device contains the composition.

Abstract: Compounds including at least one mesogenic substructure and at least one long flexible segment and methods of synthesizing the same are disclosed. Formulations which include various embodiments of the mesogen-containing compounds and their use in articles of manufacture and ophthalmic devices are also disclosed.

Abstract: The present invention relates to polymerizable compounds, to processes and intermediates for the preparation thereof, to liquid-crystal (LC) media comprising them, and to the use of the polymerizable compounds and LC media for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the PS (“polymer sustained”) or PSA (“polymer sustained alignment”) type.

Abstract: The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I, in which R1, R1*, L1, L2 and L3 have the meanings indicated in Claim 1, and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PA-VA, PALC, FFS, PS-FFS, IPS or PS-IPS effect. The invention furthermore also relates to compounds of the formula I.

Abstract: A liquid crystal composition including a polymerizable compound, and an AM device including the liquid crystal composition are described. The liquid crystal composition includes the compound (1) and the compound (2): wherein P1 and P2 are polymerizable groups; the rings A, B, C and E are 1,4-cyclohexylene or 1,4-phenylene, etc.; the ring D is 2,3-difluoro-1,4-phenylene, etc.; Z1 and Z2 are alkylene, etc.; L1, Z3 and Z4 are a single bond, etc.; R1 and R2 are alkyl, etc.; and q, r and s are 1, etc.

Abstract: A liquid crystal composition according to an exemplary embodiment of the present invention includes a liquid crystal compound represented by a below chemical formula (I) at about 10 wt % to about 15 wt %; and at least one liquid crystal compound at about 3 wt % to about 8 wt % among liquid crystal compounds represented by chemical formula (II) to chemical formula (IV). Here, X and Y may be equal to each other or different from each other, and each is an alkyl group or an alkenyl group having a carbon number of 1 to 4.

Abstract: The present invention relates to compounds represented by the following Formula Ic, in which R2-R6 can each independently be selected from hydrogen or hydrocarbyl (e.g., methyl); L1 and L4 are each independently a divalent linking group, such as a bond or —OC(O)—R8—C(O)O—, where R8 can be divalent hydrocarbyl (e.g., —CH2CH2—); each L2 and each L5 each independently represent a flexible segment, such as divalent linear or branched C1-C25 alkyl; each L3 and each L6 each independently represent a rigid segment including, for example, optionally substituted phenylen-1,4-diyl groups; t and s are each independently from 1 to 4; m and p are each independently from 0 to 4 for each t, provided that the sum of m and p is at least 1 for each t; q and r are each independently from 0 to 4 for each s, provided that the sum of q and r is at least 1 for each s; and E1 and E2 can each independently be hydrogen or hydrocarbyl.

Abstract: The present invention relates to dielectrically positive, preferably nematic, media comprising one or more polymerisable compounds of formula I in which the parameters have the meaning given in the text, to polymer-stabilized media obtained therefrom, to the use thereof in liquid-crystal displays, and to these displays, in particular PSA-IPS, PSA-FFS and PSA-positive VA displays.

Abstract: The present invention relates to a high scattering smectic liquid crystal material and display device using the same. In the present invention, a series of smectic A phase liquid crystals having compact arrangement of crystal domains or a series of smectic liquid crystal mixed materials having a degree of order higher than that of the smectic A phase and an optical texture different from that of the smectic A phase are obtained by mixing a smectic liquid crystal with an organic compound having a high optical anisotropy (?n) or mixing different types of smectic phases. When used in a smectic stable state liquid crystal display pattern, these materials have high scattering properties and can effectively improve the contrast of a smectic liquid crystal display device. The present invention also improves contrast when it used in a reflective smectic liquid crystal display device.

Abstract: The present invention relates to a liquid-crystalline medium, characterised in that it contains a polymerisable component (A) containing one more polymerisable compounds and a liquid-crystalline component (B) containing one more compounds of the general formula I in which R, rings A1 and A2, Z1, Z2, Y1, Y2, X0 and r are as defined in claim 1.

Abstract: The present invention relates to compounds of the general formula I in which the variables are each defined as follows: W is a (Y4-T2-)s(Y3-A2-)tY2—Z2 moiety, Z1, Z2 are each independently unreactive radicals as defined more specifically in the description or reactive radicals through which polymerization can be brought about, A1, A2 are each independently spacers as defined more specifically in the description, Y1 to Y5 are linking units as defined more specifically in the description, Y6 is a chemical single bond or —CO—, T1, T2 are each independently, as defined more specifically in the description, divalent saturated or unsaturated, optionally substituted and optionally fused iso- or heterocyclic radicals, Q is substituents as defined more specifically in the description, r, t are each independently 0 or 1, s is 0, 1, 2 or 3 and q is 0, 1, 2, 3 or 4.

Abstract: A liquid crystal medium having an optically isotropic liquid crystal phase is described, which has stability to heat, light and so on, a broad temperature range of liquid crystal phase, a large optical anisotropy and a large dielectric anisotropy. A liquid crystal composition is described, which includes an achiral component T and a chiral dopant and exhibits an optically isotropic liquid crystal phase. The achiral component T contains, as its first component, at least one compound selected from compounds represented by formula (1), wherein R1 is C1-10 alkyl, the rings A1 to A6 are 1,4-phenylene, Z1 to Z7 are single bonds, Y1 and Y2 are fluorine; X1 is halogen, and i, j, k, m, n, p and q are independently 0 or 1.

Abstract: The invention relates to a liquid-crystalline medium comprising one or more compounds of the formula I in which R0, X0 and L1-6 have the meanings indicated in Claim 1, and to the use thereof in electro-optical liquid-crystal displays.

Abstract: A liquid crystal composition containing a polymerizable compound according to the present invention is used in a liquid crystal display element to which a liquid crystal alignment capability is provided by polymerization. The composition contains a polymerizable compound that polymerizes without a photopolymerization initiator or with only an extremely small amount of photopolymerization initiator. Therefore, the alignment after the polymerization becomes more stable and the display characteristics do not degrade. Thus, the polymerizable compound is suitable as a practical component of the liquid crystal composition. A liquid crystal display element that uses the liquid crystal composition containing a polymerizable compound according to the present invention can be suitably used for VA and IPS liquid crystal display elements.

Abstract: The present inventions to provide a novel polymerizable chiral compound (chiral agent) having high helical twisting power, a polymerizable liquid crystal composition comprising the polymerizable chiral compound and a polymerizable liquid crystal compound, a liquid crystal polymer, and an optically anisotropic body.

Abstract: Provided is a liquid crystal composition satisfying at least one of characteristics such as a high maximum temperature of a nematic phase, a low minimum temperature of the nematic phase, a small viscosity, a large optical anisotropy, a large dielectric anisotropy, a large specific resistance, high stability to ultraviolet light and high stability to heat, or having a suitable balance regarding at least two of the characteristics. Provided is an AM device having a short response time, a large voltage holding ratio, a large contrast ratio, a long service life, etc. The liquid crystal composition having a nematic phase includes a specific three-ring or four-ring compound having a high maximum temperature and a large dielectric anisotropy as a first component, and a specific compound having a small viscosity or a high maximum temperature of the nematic phase as a second component, and a liquid crystal display device contains the composition.

Abstract: A compound which has a benzoxazinone ring and an aromatic ring that directly bonds to the benzoxazinone ring, and has a mesogenic core substituted by a substituent having a polymerizable functional group is excellent in terms of durability, colorless, and exhibits a high ?n while having an azomethine bond.

Abstract: The disclosed subject matter provides a chiral host-guest composition for a ferroelectric liquid crystal mixture, the host-guest composition comprising a chiral guest compound and an achiral host compound, wherein the host-guest composition induces a greater degree of polarization in the liquid crystal mixture than is induced in the mixture with a comparable amount of the chiral guest compound in the absence of the achiral host compound. The chiral guest is a fluorinated compound comprising a aryl or heteroaryl core substituted with an alkyl chain, wherein the alkyl chain includes one or more fluorine atoms, each fluorine atom being bonded to a chiral carbon atom. The achiral host possesses a central thiadiazole core, with at least one aryl/heteroaryl wing, further substituted with alkyl or alkoxy groups.

Abstract: A new method to control the iridescence colour of solid nanocrystalline cellulose (NCC) films by ultrasound and high-shear (mechanical) energy input to the NCC suspension prior to film formation is provided. As the energy input to the NCC suspension increases, the resulting film colour shifts from the ultraviolet region towards the infrared region of the electromagnetic spectrum; this wavelength shift lies in the opposite direction to that caused by the addition of electrolytes to NCC suspensions prior to film formation. No additives are required to achieve the changes in colour; colour changes can also be effected by mixing two suspensions exposed to different levels of sonication.

Abstract: The invention relates to compensation films for liquid-crystal displays with additions of rod-shaped liquid crystals mentioned below, to polarizer plates which have at least one compensation film of this type, to liquid-crystal displays which have compensation films of the said type, and to processes for the production of the said compensation films, polarizer plates and liquid-crystal displays, to the use of the compounds described in greater detail below as additions to compensation films for liquid-crystal displays, and to further subject-matters of the invention which can be seen below.

Abstract: To provide a liquid crystal composition satisfying at least one of characteristics such as a high maximum temperature of a nematic phase, a low minimum temperature thereof, a small viscosity, a large optical anisotropy, a large dielectric anisotropy, a large specific resistance, a large elastic constant, a high stability to ultraviolet light and heat, or a liquid crystal composition having a suitable balance regarding at least two of the characteristics; and an AM device having a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth; wherein a liquid crystal composition has a nematic phase and contains a specific compound having a high maximum temperature and a large dielectric anisotropy as a first component, and a specific compound having a small viscosity as a second component, and may contain a specific compound having a large dielectric anisotropy as a third component.

Abstract: The present invention relates to polymerizable compounds, to processes and intermediates for the preparation thereof, and to the use thereof for optical, electro-optical and electronic purposes, in particular in liquid-crystal (LC) media and LC displays, especially in LC displays of the PS (polymer stabilized) or PSA (polymer sustained alignment) type.

Abstract: The present invention relates to polymerisable compounds, to processes and intermediates for the preparation thereof, and to the use thereof for optical, electro-optical and electronic purposes, in particular in liquid-crystal (LC) media and LC displays, especially in LC displays of the PS (“polymer sustained”) or PSA (“polymer sustained alignment”) type.

Abstract: The present invention relates to liquid-crystalline compounds containing an O-heterocyclic ring, three partially fluorinated benzene rings and a —CF2O— bridge between the rings. In addition, the invention relates to liquid-crystalline media prepared therewith and to liquid-crystal display devices (LC displays) containing these media.

Abstract: A liquid crystal compound and a liquid crystal medium are described. The liquid crystal compound is stable to heat and light and has a large dielectric anisotropy and a large optical anisotropy. The liquid crystal medium has a wide temperature range of liquid crystal phase, a large optical anisotropy and a large dielectric anisotropy, and exhibits an optically isotropic liquid crystal phase. The liquid crystal compound has 4 or 5 benzene rings, one of which is a chlorofluorobenzene ring. The liquid crystal medium is characterized in containing the liquid crystal compound and a chiral dopant and exhibiting an optically isotropic liquid crystal phase.

Abstract: A liquid crystal compound having a high stability to heat, light or the like, a high clearing point, a low minimum temperature of a liquid crystal phase, a small viscosity, a suitable optical anisotropy, a large negative dielectric anisotropy, a suitable elastic constant and an excellent compatibility with other liquid crystal compounds, and a liquid crystal composition including this compound, and a liquid crystal display device containing this composition. A compound represented by formula (1-1). In the formula, for example, R1 and R2 are alkyl having 1 to 10 carbons or alkoxy having 1 to 9 carbons; ring A1 and ring A2 are 1,4-cyclohexylene, 1,4-phenylene or 2,3-difluoro-1,4-phenylene; Z1 and Z2 are a single bond or —(CH2)2—; >W1—W2— and >W4—W3— are >CH—CH2— or >C?CH—; and m and n are 0, 1 or 2, and the sum of m and n is 1 or 2.