Patent Application
20230112953
The present invention relates to a liquid crystal composition, a liquid crystal element, a sensor, a liquid crystal lens, an optical communication device, and an antenna.
Antennas formed of liquid crystals to transmit and receive radio waves between movable bodies such as automobiles and communications satellites are attracting attention as a new application for liquid crystals widely used for displays. Conventionally, satellite communications have used parabolic antennas. When used in a movable body such as an automobile, the parabolic antenna has to be pointed in a direction of the satellite as needed and requires a large moving part. An antenna formed of liquid crystals, however, can change the direction of radio wave transmission and reception by operating the liquid crystals, so there is no need to move the antenna itself, and the shape of the antenna can be flat.
In general, automatic driving of automobiles and other vehicles requires massive data downloads of high-precision 3D map information. However, an antenna formed of liquid crystals, when mounted on an automobile, enables massive data downloads from communications satellites without a mechanical moving part. The frequency band used for satellite communications is approximately 13 GHz, which is significantly different from the frequencies that have been used for liquid crystal display applications. The required physical properties of liquid crystals therefore are also significantly different. Specifically, Δn required for liquid crystals for antennas is approximately 0.4, and the operating temperature range is −40 to 120° C. or higher.
Infrared laser image recognition and ranging devices formed of liquid crystals are also attracting attention as sensors for automatic driving of movable bodies such as automobiles. The required Δn of liquid crystals for this application is 0.2 to 0.3, and the operating temperature range is −40 to 120° C. or higher.
In this respect, examples of the technology of liquid crystals for antennas include PTL 1.
NPL 1 also proposes the use of liquid crystal materials as a component of high-frequency devices.
For liquid crystals for antennas, there is a demand for the development of liquid crystal compositions that exhibit a higher refractive index anisotropy (Δn) to enable greater phase control over electromagnetic waves in the microwave or millimeter wave range. Furthermore, in the field of liquid crystal compositions for high-frequency applications such as antennas, there is a demand for those having a higher dielectric constant anisotropy (Δε) in terms of lower drive voltages and quick response. Thus, there is a need for liquid crystal compositions that combine a high Δn and a high Δε and satisfy the required characteristics for high-frequency applications. Unfortunately, in the liquid crystal compositions described in PTL 1 above, few specific values of Δn are listed. Although Δn is listed, only liquid crystal compositions with a small Δε are listed, and liquid crystal compositions that combine a high Δn and a high Δε are not disclosed.
An object of the present invention is to provide a nematic liquid crystal composition having a high Δn and a high Δε in a liquid crystal material that enables greater phase control over electromagnetic waves in the microwave or millimeter wave range, and a liquid crystal element, a sensor, a liquid crystal lens, an optical communication device, and an antenna including the nematic liquid crystal composition.
The inventors of the present invention have conducted elaborate studies and found that the above object can be achieved by a liquid crystal composition containing one or two or more compounds represented by general formula (i) and one or two or more compounds represented by general formula (ii) described below. This finding has led to completion of the present invention.
The overall configuration of the present invention to achieve the above object is as follows.
A liquid crystal composition of the present invention contains:
one or two or more compounds represented by general formula (i) below:
(in general formula (i),
Ri1 represents an alkyl group having 1 to 12 carbon atoms, wherein one or two or more non-adjacent —CH2-'s in the alkyl group are each independently optionally substituted with —CH═CH—, —C≡C—, —O—, —CO—, —COO—, or —OCO—, and one or two or more hydrogen atoms in Ri1 are each independently optionally substituted with a fluorine atom,
Ai1, Ai2, and Ai3 each independently represent a group selected from the group consisting of the following groups (a) to (c):
(a) a 1,4-cyclohexylene group (one —CH2— or two or more non-adjacent —CH2-'s in this group are optionally substituted with —O—),
(b) a 1,4-phenylene group (one —CH═ or two or more non-adjacent —CH='s in this group are optionally substituted with —N═), and
(c) a naphthalene-2,6-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, or a decahydronaphthalene-2,6-diyl group (one —CH═ or two or more non-adjacent —CH='s in the naphthalene-2,6-diyl group or the 1,2,3,4-tetrahydronaphthalene-2,6-diyl group are optionally substituted with —N═),
hydrogen atoms in the group (a), the group (b), and the group (c) are each independently optionally substituted with a halogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms,
Zi1 and Zi2 each independently represent —OCH2—, —CH2O—, —C2H4—, —C4H8—, —COO—, —OCO—, —CH═CH—, —CF═CF—, —CF2O—, —OCF2—, —CF2CF2—, —C≡C—, or a single bond, wherein at least one Zi1 or Zi2 represents —C≡C—,
mi1 represents 1 or 2,
a plurality of Ai1s, if present, may be the same or different, and a plurality of Zi1s, if present, may be the same or different); and
one or two or more compounds represented by general formula (ii) below:
(in general formula (ii),
Rii1 and Rii2 each independently represent a fluorine atom, a chlorine atom, a cyano group, or an alkyl group having 1 to 12 carbon atoms, wherein one or two or more non-adjacent —CH2-'s in the alkyl group are each independently optionally substituted with —CH═CH—, —C≡C—, —O—, —CO—, —COO— or —OCO—, and one or two or more hydrogen atoms in Rii1 and Rii2 are each independently optionally substituted with a fluorine atom, wherein Rii1 and Rii2 do not simultaneously represent a substituent selected from a fluorine atom, a chlorine atom, and a cyano group,
Zii1, Zii2, and Zii3 each independently represent a single bond, —OCH2—, —CH2O—, —C2H4—, —C4H8—, —COO—, —OCO—, —CH═CH—, —CF═CF—, —CF2O—, —OCF2—, —CF2CF2—, or —C≡C—,
Aii1, Aii2, Aii3, Aii4, Aii5, and Aii6 each independently represent a group selected from the group consisting of the following groups (a) to (c):
(a) a 1,4-cyclohexylene group (one CH2— or two or more non-adjacent —CH2-'s in this group are optionally substituted with —O—),
(b) a 1,4-phenylene group (one —CH═ or two or more non-adjacent —CH='s in this group are optionally substituted with —N═), and
(c) a naphthalene-1,4-diyl group, a naphthalene-2,6-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, or a decahydronaphthalene-2,6-diyl group (one —CH═ or two or more non-adjacent —CH='s in the naphthalene-1,4-diyl group, the naphthalene-2,6-diyl group, or the 1,2,3,4-tetrahydronaphthalene-2,6-diyl group are optionally substituted with —N═),
hydrogen atoms in the group (a), the group (b), and the group (c) are each independently optionally substituted with a halogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms, and
mii1, mii2, and mii3 each independently represent 0 or 1, wherein mii1+mii2+mii3 represents 0 or 1).
A liquid crystal element of the present invention includes the above liquid crystal composition.
A sensor of the present invention includes the above liquid crystal composition.
A liquid crystal lens of the present invention includes the above liquid crystal composition.
An optical communication device of the present invention includes the above liquid crystal composition.
An antenna of the present invention includes the above liquid crystal composition.
The present invention can provide a nematic liquid crystal composition having a high refractive index anisotropy (Δn) and a high dielectric constant anisotropy (Δε) and further can provide a liquid crystal element, a sensor, a liquid crystal lens, an optical communication device, and particularly an antenna including the nematic liquid crystal composition.
A liquid crystal composition, a liquid crystal element, a sensor, a lens, an optical communication device, and an antenna of the present invention will be described in detail below based on embodiments thereof.
A liquid crystal composition according to the present invention contains a compound represented by general formula (i) and a compound represented by general formula (ii). The compounds represented by general formula (i) and general formula (ii) are described in order below. The compound represented by general formula (i) has a high Δε and a relatively high Δn and has even more favorable miscibility. Because of this, a liquid crystal composition stable at room temperature can be provided.
The liquid crystal compound represented by general formula (i) in the present invention is as follows.
In general formula (i), Ri1 represents an alkyl group having 1 to 12 carbon atoms, wherein one or two or more non-adjacent —CH2-'s in the alkyl group are each independently optionally substituted with —CH═CH—, —C≡C—, —O—, —CO—, —COO—, or —OCO—, and one or two or more hydrogen atoms in Ri1 are each independently optionally substituted with a fluorine atom.
Ri1 is a linear or branched group and preferably a linear group. Ri1 preferably represents an alkyl group having 2 to 11 carbon atoms, more preferably an alkyl group having 3 to 9 carbon atoms, and even more preferably an alkyl group having 4 to 7 carbon atoms.
Examples of the alkyl group in the present description include, but not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isodecyl, dodecyl, and 2-ethylhexyl, and a linear alkyl group is preferred.
A methylene group in Ri1 in general formula (i) is optionally substituted with —CH═CH—, —C≡C—, —O—, —CO—, —COO—, or —OCO— such that oxygen atoms are not directly adjacent to each other. Specifically, Ri1 is preferably an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkenyloxy group having 2 to 8 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms, even more preferably an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and even more preferably an alkyl group having 2 to 5 carbon atoms or an alkenyl group having 2 to 3 carbon atoms.
When the reliability of the entire liquid crystal composition is important, Ri1 is preferably an alkyl group. When the viscosity of the entire liquid crystal composition is important, Ri1 is preferably an alkenyl group.
The alkenyl group in the present description is preferably selected from groups represented by any of formulae (R1) to (R5). (The black circle in each formula represents a carbon atom in a ring structure.)
The alkenyloxy group in the present description is preferably selected from groups represented by any of formulae (R6) to (R10). (The black circle in each formula represents a carbon atom in a ring structure.)
The alkoxy group in the present description includes, but not limited to, methoxy, ethoxy, propoxy, butoxy, pentoxy, and hexoxy, and a linear alkoxy group is preferred.
When the ring structure to which Ri1 is bonded is a phenyl group (aromatic group), a linear alkyl group having 1 to 5 carbon atoms, a linear alkoxy group having 1 to 4 carbon atoms, and an alkenyl group having 4 to 5 carbon atoms are preferred. When the ring structure to which it is bonded is a saturated ring structure such as cyclohexane, pyran, and dioxane, a linear alkyl group having 1 to 5 carbon atoms, a linear alkoxy group having 1 to 4 carbon atoms, and a linear alkenyl group having 2 to 5 carbon atoms are preferred. To stabilize the nematic phase, the total number of carbon atoms and oxygen atoms, if present, is preferably 5 or less, and preferably they are linear.
In general formula (i), Ai1, Ai2, and Ai3 each independently represent a divalent cyclic group in which one or two or more hydrogen atoms in the ring structure are each independently optionally substituted with a halogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms. The cyclic group is any of groups (a) to (c), and formula (a) or (b) is more preferred. Hydrogen atoms in the group (a), the group (b), and the group (c) are each independently optionally substituted with a halogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms.
(a) a 1,4-cyclohexylene group (one —CH2— or two or more non-adjacent —CH2-'s in this group are optionally substituted with —O—),
(b) a 1,4-phenylene group (one —CH═ or two or more non-adjacent —CH='s in this group are optionally substituted with —N═), and
(c) a naphthalene-2,6-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, or a decahydronaphthalene-2,6-diyl group (one —CH═ or two or more non-adjacent —CH='s in the naphthalene-2,6-diyl group or the 1,2,3,4-tetrahydronaphthalene-2,6-diyl group are optionally substituted with —N═.)
Specific examples of Ai1, Ai2, and Ai3 include divalent cyclic groups represented by formulae (a1) to (a26) below.
(In the above formulae, * represents a bond with a carbon atom or another atom.)
Among the above divalent cyclic groups, (a1) to (a3), (a5) to (a6), (a9) to (a10), and (a12) to (a25) are preferred, (a1) to (a3), (a5) to (a6), and (a12) to (a25) are more preferred, and (a1) to (a3) and (a12) to (a26) are even more preferred. In terms of improving Δn, (a5) to (a6), (a9) to (a10), and (a12) to (a26) are preferred, and (a1) to (a3), (a5) to (a6), and (a12) to (a26) are more preferred. In terms of further improving Δε, it is preferable that at least one or more of Ai1, Ai2, and Ai3 have (a12), (a14), (a16), (a17), (a18), (a19), (a21), (a23), (a24), (a25), or (a26).
A plurality of Ai1s, if present, may be the same or different.
In general formula (i), Zi1 and Zi2 each independently represent —OCH2—, —CH2O—, —C2H4—, —C4H8—, —COO—, —OCO—, —CH═CH—, —CF═CF—, —CF2O—, —OCF2—, —CF2CF2—, —C≡C—, or a single bond, wherein at least one Zi1 or Zi2 represents —C≡C—.
When Zi1 and Zi2 satisfy the above condition, a linking group between the ring structures forming mesogen easily ensures molecular linearity.
Since at least one of Zi1 and mi1 Zi2s represents —C≡C— in general formula (i), the compound represented by general formula (i) has at least one —C≡C— in its structure.
Preferably, Zi1 and Zi2 are independently a single bond, —C≡C—, —CH═CH—, or —CF═CF—. Zi1 and Zi2 are preferably each independently a single bond when the stability of the liquid crystal composition is important, and preferably —C≡C— when Δn is important.
A plurality of Zi1s, if present, may be the same or different.
mi1 represents 1 or 2, and preferably 1. When mi1 is 1 or 2, the compound represented by general formula (i) corresponds to a tricyclic or tetracyclic liquid crystal compound and exhibits high miscibility with other liquid crystal compounds.
Ai1, Ai2, and Ai3, which are ring structures in a molecule of the compound represented by general formula (i) in the present invention, preferably have 1 to 5 fluorine atoms in total, and more preferably have 1 to 4 fluorine atoms.
Ai1, Ai2, and Ai3, which are ring structures in a molecule of the compound represented by general formula (i) in the present invention, preferably have 0 to 3 halogen atoms (other than fluorine atoms) in total, and more preferably have 0 to 2 halogen atoms.
Ai1, Ai2, and Ai3, which are ring structures in a molecule of the compound represented by general formula (i) in the present invention, preferably have 1 to 5 halogen atoms (including fluorine atoms) in total, and more preferably have 1 to 4 halogen atoms.
The compound represented by general formula (i) in the present invention has a cyano group bonded to Ai3. In addition to the cyano group, Ai1, Ai2, and Ai3 which are ring structures in a molecule may have 1 to 3 cyano groups in total.
In the liquid crystal composition according to the present invention, the compounds represented by general formula (i) may be used singly or in combination of two or more. The kinds of compounds that can be combined are not limited, and the compounds are used in appropriate combinations according to the desired performance, such as dielectric constant anisotropy, solubility at room temperature, transition temperature, and birefringence index. For example, one kind of liquid crystal compound is used in one embodiment of the present invention. Alternatively, in another embodiment of the present invention, two kinds, three kinds, four kinds, five kinds, six kinds, seven kinds, eight kinds, nine kinds, or ten or more kinds are used.
The lower limit (% by mass) of the preferred amount of the compound represented by general formula (i) in the total amount of the liquid crystal composition of the present invention is 1%, 2%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 22%, 25%, 30%, 40%, 50%, 55%, 60%, 65%, and 70%. In terms of preventing inconvenience such as precipitation, the upper limit of the preferred amount is 85%, 80%, 75%, 70%, 65%, 55%, 45%, 35%, 30%, 28%, 25%, 23%, 20%, 18%, and 15%.
A preferred form of the compound represented by general formula (i) of the present invention is a compound in which, in general formula (i), Ri1 is a linear alkyl group or alkoxy group having 1 to 8 carbon atoms, a linear alkenyl group or alkenyloxy group having 2 to 8 carbon atoms, Ai1, Ai2, and Ai3 are the above formulae (a1) to (a3), (a19), or (a24), Zi1 and Zi2 are each independently a single bond, —COO—, or —C≡C—, and Zi1 or Zi2 is —C≡C—, and mi1 represents 1. The preferred amount of the compound represented by general formula (i) is preferably 5 to 85% by mass, more preferably 10 to 83% by mass, and particularly preferably 13 to 80% by mass of the entire liquid crystal composition (100% by mass).
The compound represented by general formula (i) is preferably a compound represented by general formula (i-1) below.
(In general formula (i-1), Ri1, Ai1, Zi1, Zi2, and mi1 respectively have the same meaning as Ri1, Ai1, Zi1, Zi2, and mi1 in general formula (i), and Xi1 to Xi6 each independently represent a hydrogen atom or a fluorine atom, wherein Xi1 and Xi2 do not simultaneously represent a fluorine atom, and Xi3 and Xi4 do not simultaneously represent a fluorine atom.)
Ri1, Ai1, Zi1, Zi2, and mi1 in general formula (i-1) are the same as Ri1, Ai1, Zi1, Zi2, and mi1 in general formula (i) and are not further elaborated here.
In Xi1 to Xi6, Xi1 and Xi2 do not simultaneously represent a fluorine atom, and Xi3 and Xi4 do not simultaneously represent a fluorine atom, whereby the liquid crystal compound represented by general formula (i) easily exhibits a dielectric constant anisotropy (Δε) of 0 or more.
In terms of increasing the positive value of the dielectric constant anisotropy, preferably, at least one or more of Xi2, Xi4, Xi5, and Xi6 represents a fluorine atom. Introducing a halogen atom such as a fluorine atom at the lateral position of the ring structure is preferred because if so, the miscibility is improved. The use of the compound represented by general formula (i-1) easily ensures storage stability at room temperature.
mi1 Ai1s and two benzene rings, which are ring structures in a molecule of the compound represented by general formula (i-1) in the present invention, preferably have 1 to 5 fluorine atoms in total, and more preferably have 1 to 4 fluorine atoms.
mi1 Ai1s, which are ring structures in a molecule of the compound represented by general formula (i-1) in the present invention, preferably have 0 to 3 halogen atoms (other than fluorine atoms) in total, and more preferably have 0 to 2 halogen atoms.
mi1 Ai1s and two benzene rings, which are ring structures in a molecule of the compound represented by general formula (i-1) in the present invention, preferably have 1 to 5 halogen atoms (including fluorine atoms) in total, and more preferably have 1 to 4 halogen atoms.
mi1 Ai1s, which are ring structures in a molecule of the compound represented by general formula (i-1) in the present invention, preferably have 0 to 3 cyano groups in total, and more preferably have 0 to 2 cyano groups.
Examples of a preferred form of the compounds represented by general formula (i) and general formula (i-1) include compounds represented by general formulae (i-1-a) to (i-1-d) below.
In general formulae (i-1-a) to (i-1-d), Ri11 represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or an alkenyloxy group having 2 to 8 carbon atoms, the ring X and the ring Y each independently represent a divalent cyclic group represented by formulae (a1) to (a26), and Xi1, Xi2, Xi3, Xi4, Xi5, and Xi6 each independently represent a hydrogen atom or a fluorine atom.
In general formulae (i-1-a) to (i-1-d), more preferably, the ring X and the ring Y are each independently (a1) to (a3), (a19), or (a24).
In general formulae (i-1-a) to (i-1-d), Ri1 is preferably an alkyl group having 1 to 8 carbon atoms in terms of reliability. Among the compounds above, (i-1-a), (i-1-b), and (i-1-c) are preferred.
Examples of a preferred form of the compounds represented by general formula (i) and general formula (i-1) include a compound represented by general formula (i-1-1) below. The compound represented by general formula (i-1-1) has a relatively high Δn and favorable miscibility. Because of this, a liquid crystal composition stable at room temperature can be obtained.
(In general formula (i-1-1), Ri1, Xi1 to Xi6, and Ai1 respectively have the same meaning as Ri1, Xi1 to Xi6, and Ai1 in general formula (i) or general formula (i-1),
Xi7, Xi8, and Xi9 each independently represent a hydrogen atom or a fluorine atom, wherein Xi7 and Xi8 do not simultaneously represent a fluorine atom,
Zi12 represents a single bond or —C≡C—,
Zi13 represents a single bond or —C≡C—, wherein at least one Zi2 or Zi3 represents —C≡C—, and
mi2 represents 0 or 1.)
In general formula (i-1-1), Ri1, Xi1 to Xi6, and Ai1 are the same as Ri1, Xi1 to Xi6, and Ai1 and Zi1 in general formula (i) or general formula (i-1) and are not further elaborated here.
In general formula (i-1-1), Xi7 and Xi8 do not simultaneously represent a fluorine atom, whereby the liquid crystal compound represented by general formula (i-1-1) easily exhibits a dielectric constant anisotropy (Δε) of 0 or more.
In terms of stability of the liquid crystal composition, preferably, one of Zi12 and Zi13 represents —C≡C— and the other represents a single bond.
In the compound represented by general formula (i-1-1) according to the present invention, preferably, at least one of Xi1 to Xi7 is a fluorine atom. That is, in a molecule of the compound represented by general formula (i-1-1) in the present invention, the benzene ring has a total of one or two or more fluorine atoms that are electron-withdrawing groups. Thus, the compound represented by general formula (i-1-1) more easily exhibits positive dielectric constant anisotropy, and introducing a halogen atom such as a fluorine atom at the lateral position of the ring structure is preferred because if so, the miscibility is improved. The use of the compound represented by general formula (i-1-1) easily ensures storage stability at room temperature.
Ai1 and three benzene rings, which are ring structures in a molecule of the compound represented by general formula (i-1-1) in the present invention, preferably have 1 to 5 halogen atoms (including fluorine atoms) in total, and more preferably have 1 to 4 halogen atoms.
As specific structures of general formula (i) according to the present invention, tricyclic or tetracyclic liquid crystal compounds represented by general formulae (i.1) to (i.26) below are preferred. Tricyclic compounds are more preferred in terms of further improving the miscibility of the liquid crystal composition. In the liquid crystal composition according to the present invention, the compounds represented by general formulae (i.1) to (i.26) may be used singly or in combination of two or more.
In general formulae (i.1) to (i.26), preferably, Ri1 represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyloxy group having 1 to 6 carbon atoms.
Among the compounds represented by general formulae (i.1) to (i.26), (i.8) to (i.23) are preferred.
In the liquid crystal composition according to the present invention, the preferred amount of general formula (i) can be used as the amount of each of the compounds in general formulae (i.1) to (i.26) in the entire liquid crystal composition.
Examples of a preferred form of the compounds represented by general formula (i) and general formula (i-1) include a compound represented by general formula (i-1-1a) below. The compound represented by general formula (i-1-1a) has a tolan structure and has a cyano group at a terminal of the ring structure and has a fluorine atom in Xi4, thereby improving Δε.
(In general formula (i-1-1a), Ri1, Ai1, Zi1, and Xi1 to Xi3, Xi5, and Xi6 respectively have the same meaning as Ri1, Ai1, Zi1, Xi1 to Xi3, Xi5, and Xi6 in general formula (i-1),
mi2 represents 0 or 1,
Zia1 and Zia2 each independently represent a single bond or —C≡C—, wherein at least one of these represents —C≡C—,
Xi7 to Xi9 each independently represent a hydrogen atom or a fluorine atom, wherein Xi7 and Xi8 do not simultaneously represent a fluorine atom, and
in general formula (i-1-1a), at least one of Xi2, Xi5, Xi6, Xi8, and Xi9 represents a fluorine atom.)
In general formula (i-1-1a), Ri1, Ai1, Zi1, and Xi1 to Xi3, Xi5, and Xi6 are the same as Ri1, Ai1, Zi1, and Xi1 to Xi3, Xi5, and Xi6 in general formula (i) or general formula (i-1) and are not further elaborated here.
In terms of stability of the liquid crystal composition, preferably, one of Zia1 and Zia2 represents —C≡C— and the other represents a single bond.
Ai1 and three benzene rings, which are ring structures in a molecule of the compound represented by general formula (i-1-1a) in the present invention, preferably have 1 to 5 halogen atoms (including fluorine atoms) in total, and more preferably have 1 to 4 halogen atoms.
As specific structures of general formula (i) and general formula (i-1-1a) according to the present invention, tricyclic or tetracyclic liquid crystal compounds represented by general formulae (i.27) to (i.44) below are preferred. Tricyclic compounds are more preferred in terms of further improving the miscibility of the liquid crystal composition. In the liquid crystal composition according to the present invention, the compounds represented by general formulae (i.27) to (i.44) may be used singly or in combination of two or more.
In general formulae (i.27) to (i.44), Ri1 has the same meaning as Ri1 in general formula (i) but preferably represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyloxy group having 1 to 6 carbon atoms.
Among the compounds represented by general formulae (i.27) to (i.44), (i.27) to (i.34) are preferred.
In the liquid crystal composition according to the present invention, the preferred amount of general formula (i) can be used as the amount of each of the compounds in general formulae (i.27) to (i.44) in the entire liquid crystal composition.
The compound represented by general formula (i-1-1a) can be produced by a known method and can be produced, for example, by the following method.
(In the formulae, Ri1, Ai1, Zi1, Xi1 to Xi3, and Xi5 to Xi9 respectively have the same meaning as Ri1, Ai1, Zi1, Xi1 to Xi3, and Xi5 to Xi9 in general formula (i-1-1a).)
The compound represented by general formula (I-1) is allowed to react with the compound represented by general formula (I-2) to yield the compound represented by general formula (I-3). Examples of the reaction method include the Sonogashira coupling reaction using a palladium catalyst, a copper catalyst, and a base. Specific examples of the palladium catalyst include those listed above. Specific examples of the copper catalyst include copper(I) iodide. Specific examples of the base include triethylamine.
The compound represented by general formula (I-3) is allowed to reach with, for example, sec-butyllithium and iodine to yield the compound represented by general formula (I-4).
The compound represented by general formula (I-4) is allowed to react with, for example, bis(pinacolato)diboron to yield the compound represented by general formula (I-5).
The compound represented by general formula (I-6) is allowed to react with the compound represented by general formula (I-5) to yield the compound represented by general formula (i-1-1a). Examples of the reaction method include cross-coupling in the presence of a metal catalyst and a base. Specific examples of the metal catalyst include [1,1′-bis(diphenylphosphino)ferrocene]palladium(II) dichloride, palladium(II) acetate, dichlorobis[di-tert-butyl(p-dimethylaminophenyl)phosphino]palladium(II), and tetrakis(triphenylphosphine)palladium(0). When palladium(II) acetate is used as the metal catalyst, a ligand such as triphenylphosphine or 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl may be added. Specific examples of the base include potassium carbonate, potassium phosphate, and cesium carbonate.
The liquid crystal composition according to the present invention contains one or two or more compounds represented by general formula (ii). The compound represented by general formula (ii) is as follows.
The compound represented by general formula (ii) has a high Δn. The compound represented by general formula (ii) has excellent miscibility with the compound represented by general formula (i) and can be combined with the compound represented by general formula (i) to provide a liquid crystal composition that combines a high Δn and a high Δε.
In general formula (ii), Rii1 and Rii2 each independently represent a fluorine atom, a chlorine atom, a cyano group, or an alkyl group having 1 to 12 carbon atoms, wherein one or two or more non-adjacent —CH2-'s in the alkyl group are each independently optionally substituted with —CH═CH—, —C≡C—, —O—, —CO—, —COO—, or —OCO—, and one or two or more hydrogen atoms in Rii1 and Rii2 are each independently optionally substituted with a fluorine atom, wherein Rii1 and Rii2 do not simultaneously represent a substituent selected from a fluorine atom, a chlorine atom, and a cyano group.
In general formula (ii), Rii1 is preferably an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkenyloxy group having 2 to 8 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms, even more preferably an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and even more preferably an alkyl group having 2 to 5 carbon atoms or an alkenyl group having 2 to 3 carbon atoms.
When the reliability is important, Rii1 is preferably an alkyl group. When lower viscosity is important, Rii1 is preferably an alkenyl group.
When the ring structure to which Rii1 is bonded is a phenyl group (aromatic group), a linear alkyl group having 1 to 5 carbon atoms, a linear alkoxy group having 1 to 4 carbon atoms, and an alkenyl group having 4 to 5 carbon atoms are preferred. When the ring structure to which Rii1 is bonded is a saturated ring structure such as cyclohexane, pyran, and dioxane, a linear alkyl group having 1 to 5 carbon atoms, a linear alkoxy group having 1 to 4 carbon atoms, and a linear alkenyl group having 2 to 5 carbon atoms are preferred. To stabilize the nematic phase, Rii1 preferably has a total number of carbon atoms and, if present, oxygen atoms of 5 or less and preferably is linear.
Here, the alkenyl group is preferably selected from groups represented by any of formulae (R1) to (R5) above.
Rii2 is preferably a fluorine atom, a cyano group, a trifluoromethyl group, or a trifluoromethoxy group when the compound represented by general formula (ii) is what is called a p-type compound with a positive Δε, and a fluorine atom or a cyano group is preferred.
When the compound represented by general formula (ii) is what is called a nonpolar compound in which Δε is almost zero, Rii2 has the same meaning as Rii1, wherein Rii2 and Rii1 may be the same or different.
In general formula (ii), Zii1, Zii2, and Zii3 each independently represent a single bond, OCH2—, —CH2O—, —C2H4—, —C4H8—, —COO—, —OCO—, —CH═CH—, —CF═CF—, —CF2O—, —OCF2—, —CF2CF2, or —C≡C—.
Here, Zii1 to Zii3 are preferably single bonds.
In general formula (ii), Aii1, Aii2, Aii3, Aii4, Aii5, and Aii6 each independently represent a group selected from the group consisting of the following groups (a) to (c).
(a) a 1,4-cyclohexylene group (one —CH2— or two or more non-adjacent —CH2-'s in this group are optionally substituted with —O—.)
(b) a 1,4-phenylene group (one —CH═ or two or more non-adjacent —CH='s in this group are optionally substituted with —N═.)
(c) a naphthalene-1,4-diyl group, a naphthalene-2,6-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, or a decahydronaphthalene-2,6-diyl group (one —CH═ or two or more non-adjacent —CH='s in the naphthalene-1,4-diyl group, the naphthalene-2,6-diyl group, or the 1,2,3,4-tetrahydronaphthalene-2,6-diyl group are optionally substituted with —N═.)
One or two or more hydrogen atoms in the group (a), the group (b), and the group (c) are each independently optionally substituted with a halogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms.
Aii1 to Aii6 are each independently preferably aromatic when a higher Δn is required, and preferably aliphatic in order to improve the response speed, and each independently preferably represent a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group, a 3-fluoro-1,4-phenylene group, a 3,5-difluoro-1,4-phenylene group, a 1,4-cyclohexenylene group, a 1,4-bicyclo[2.2.2]octylene group, a piperidine-1,4-diyl group, a naphthalene-2,6-diyl group, a decahydronaphthalene-2,6-diyl group, or a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, and more preferably represent the following structure:
(R represents an alkyl group having 1 to 6 carbon atoms.) particularly preferably a 1,4-phenylene group, a naphthalene-2,6-diyl group, and a tetrahydronaphthalene-2,6-diyl group, wherein one or two or more hydrogens in the 1,4-phenylene group, the naphthalene-2,6-diyl group, and the tetrahydronaphthalene-2,6-diyl group are each independently optionally substituted with a fluorine atom or an alkyl group having 1 to 6 carbon atoms.
Aii2 preferably represents a group selected from the group consisting of the following groups (d) to (f):
(Xiid1, Xiid2, Xiie1, Xiie2, Xiif1, and Xiif2 each independently represent a hydrogen atom or a fluorine atom)
in terms of improving Δn. The group (f) is preferred in terms of miscibility with other liquid crystal compounds.
In order to enhance the miscibility with other liquid crystal compositions, at least one of Aii1 to Aii6 preferably represents a 1,4-phenylene group substituted with an alkyl group having 1 to 6 carbon atoms, and more preferably represents a 1,4-phenylene group substituted with an ethylene group.
In general formula (ii), mii1, mii2, and mii3 each independently represent 0 or 1, where mii1+mii2+mii3 represents 0 or 1.
Here, mii1 is preferably 0 when the solubility in the liquid crystal composition is important, and preferably 1 when Δn and Tni are important.
Preferably, mii1+mii2+mii3 is 0.
Ai1 to Ai6, which are ring structures in a molecule of the compound represented by general formula (ii) in the present invention, preferably have 1 to 5 fluorine atoms in total, and more preferably have 1 to 4 fluorine atoms.
Ai1 to Ai6, which are ring structures in a molecule of the compound represented by general formula (ii) in the present invention, preferably have 0 to 3 halogen atoms (other than fluorine atoms) in total, and more preferably have 0 to 2 halogen atoms.
Ai1 to Ai6, which are ring structures in a molecule of the compound represented by general formula (ii) in the present invention, preferably have 1 to 5 halogen atoms (including fluorine atoms) in total, and more preferably have 1 to 4 halogen atoms.
In the liquid crystal composition according to the present invention, the compounds represented by general formula (ii) may be used singly or in combination of two or more. The kinds of compounds that can be combined are not limited, and the compounds are used in appropriate combinations according to the desired performance, such as dielectric constant anisotropy, solubility at room temperature, transition temperature, and birefringence index. For example, one kind of liquid crystal compound is used in one embodiment of the present invention. Alternatively, in another embodiment of the present invention, two kinds, three kinds, four kinds, five kinds, six kinds, seven kinds, eight kinds, nine kinds, or ten or more kinds are used.
The lower limit (% by mass) of the preferred amount of the compound represented by general formula (ii) in the total amount of the liquid crystal composition of the present invention is 1%, 2%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 22%, 25%, 30%, 40%, 50%, 55%, 60%, 65%, and 70%. In terms of preventing inconvenience such as precipitation, the upper limit of the preferred amount is 70%, 65%, 55%, 45%, 35%, 30%, 28%, 25%, 23%, 20%, 18%, and 15%.
The compound represented by general formula (ii) is preferably a compound represented by general formula (ii-1) below.
(In general formula (ii-1), Rii1, Rii2, Zii1, Zii2, Zii3, Aii1, Aii4, Aii6, mii1, mii2, and mii3 respectively have the same meaning as Rii1, Rii2, Zii1, Zii2, Zii3, Aii1, Aii4, Aii6, mii1, mii2, and mii3 in general formula (ii),
Aii2 represents a group selected from the group consisting of the following groups (d) to (f):
(Xiid1, Xiid2, Xiie1, Xiie2, Xiif1, and Xiif2 each independently represent a hydrogen atom or a fluorine atom)
Xii1, Xii2, Xii3, and Xii4 each independently represent a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms.)
In general formula (ii-1), Rii1, Rii2, Zii1, Zii2, Zii3, Aii1, Aii4, Aii6, mii1, mii2 and mii3 are the same as Rii1, Rii2, Zii1, Zii2, Zii3, Aii1, Aii4, Aii6, mii1, mii2, and mii3 in general formula (ii) and are not further elaborated here.
Xiid1, Xiid2, Xiie1, Xiie2, Xiif1, and Xiif2 each independently represent a hydrogen atom or a fluorine atom, preferably one of them is a fluorine atom in terms of improving Δε, and more preferably they all are fluorine atoms.
Preferably, at least one of Xii1, Xii2, Xii3, and Xii4 is a fluorine atom in terms of improving Δε. The total number of fluorine atoms of Xiii, Xii2, Xii3, and Xii4 is preferably 0 to 3, and more preferably 0 to 2.
Xii1, Xii2, Xii3, and Xii4 are preferably an alkyl group having 1 to 6 carbon atoms in terms of miscibility, and more preferably an ethyl group.
The ring structure to which Xii1 and Xii2 are bonded and the ring structure to which Xii3 and Xii4 are bonded are each preferably the following structure.
(Et represents an ethyl group.)
As specific structures of general formula (ii) according to the present invention, tricyclic or tetracyclic compounds represented by general formulae (ii.1) to (ii.38) below are preferred. Tricyclic compounds are more preferred in terms of further improving the miscibility of the liquid crystal composition. In the liquid crystal composition according to the present invention, the compounds represented by general formulae (ii.1) to (ii.38) may be used singly or in combination of two or more.
In general formula (ii.1) to general formula (ii.38), Rii1 and Rii2 each independently represent the same meaning as Rii1 and Rii2 in general formula (ii), wherein Rii1 preferably represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyloxy group having 1 to 6 carbon atoms. Rii2 preferably represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyloxy group having 1 to 6 carbon atoms, a fluorine atom, or a chlorine atom.
Among the compounds represented by general formula (ii.1) to general formula (ii.38), general formulae (ii-1), (ii-10) to (ii-11), and (ii-25) to (ii-29) are preferred.
Examples of a preferred form of the compounds represented by general formula (ii) and general formula (ii-1) include a compound represented by general formula (ii-1a) below. The compound represented by general formula (ii-1a) has a tolan structure and has two or more electron-withdrawing groups represented by fluorine atoms, chlorine atoms, or cyano atoms in a molecule, thereby improving Δε.
(In general formula (ii-1a), Rii1, Xiid1, and Xiid2 have the same meaning as Rii1, Xiid1, and Xiid2 in general formula (ii-1),
Riia2 represents a fluorine atom, a chlorine atom, a cyano group, or an alkyl group having 1 to 12 carbon atoms, wherein one or two or more non-adjacent —CH2-'s in the alkyl group are each independently optionally substituted with —CH═CH—, —C≡C—, —O—, —CO—, —COO— or OCO—, and one or two or more hydrogen atoms in Rii1 are each independently optionally substituted with a fluorine atom, wherein Rii1 and Riia2 do not simultaneously represent a substituent selected from a fluorine atom, a chlorine atom, and a cyano group,
Xiia1 and Xiia2 each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 6 carbon atoms, and
Xiia3, Xiia4, and Xiia5 each independently represent a hydrogen atom, a fluorine atom, or a chlorine atom, wherein at least one of Xiia3, Xiia4, and Xiia5 represents a fluorine atom or a chlorine atom.)
In general formula (ii-1a), Rii1, Xiid1, and Xiid2 are the same as Rii1, Xiid1, and Xiid2 in general formula (ii) or general formula (ii-1) and are not further elaborated here.
In general formula (ii-1a), in terms of improving solubility, at least one of Xiia1 and Xiia2 preferably represents an alkyl group having 1 to 6 carbon atoms, and more preferably represents an ethyl group.
In general formula (ii-1a), in terms of further improving Δε, at least one or more of Xiia3 and Xiia4 represents a fluorine atom or a chlorine atom.
In general formula (ii-1a), when Riia2 represents a chlorine atom or a cyano group, preferably, Xiia3 represents a fluorine atom.
Three benzene rings, which are ring structures in a molecule of the compound represented by general formula (ii-1a) in the present invention, preferably have 1 to 5 halogen atoms (including fluorine atoms) in total, and more preferably have 1 to 4 halogen atoms.
As specific structures of general formula (ii) and general formula (ii-1a) according to the present invention, liquid crystal compounds represented by general formulae (ii-41) to (ii-52) below are preferred. In the liquid crystal composition according to the present invention, the compounds represented by general formulae (ii-41) to (ii-54) may be used singly or in combination of two or more.
In general formula (ii-41) to general formula (ii-54), Rii1 and Rii2 each independently represent the same meaning as Rii1 and Rii2 in general formula (ii), wherein Rii1 preferably represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyloxy group having 1 to 6 carbon atoms. Et represents an ethyl group.
In the liquid crystal composition according to the present invention, the preferred amount of general formula (ii) can be used as the amount of each of the compounds in general formula (ii-41) to general formula (ii-54) in the entire liquid crystal composition.
The compound represented by general formula (ii-1a) can be produced by a known method and can be produced, for example, by the following method.
(In the formulae, Rii1, Riia2, Xiia1 to Xiia5, Xiid1, and Xiid2 respectively have the same meaning as Rii1, Riia2, Xiia1 to Xiia5, Xiid1, and Xiid2 in general formula (ii-1a).)
The compound represented by general formula (II-1) is allowed to react with the compound represented by general formula (II-2) to yield the compound represented by general formula (II-3).
The compound represented by general formula (II-3) is allowed to react with the compound represented by general formula (II-4) to yield the compound represented by general formula (ii-1a).
Examples of a preferred specific form of the compounds represented by general formula (ii) and general formula (ii-1) include compounds represented by structural formulae (ii-1.1) to (ii-1.96) below.
In the formulae, Xs each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 6 carbon atoms.
In the formulae, Xs each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 6 carbon atoms.
Among the compounds represented by structural formulae (ii-1.1) to (ii-1.96), (ii-1.2) to (ii-1.8), (ii-1.12) to (ii-1.18), (ii-1.22) to (ii-1.28), (ii-1.32) to (ii-1.38), and (ii-1.41) to (ii-1.96) are preferred.
In the liquid crystal composition of the present invention, if the amount of the compound represented by general formula (ii) is small, its effect is small, and therefore the lower limit of the preferred amount in the composition is 1% by mass, 2% by mass, 5% by mass, 7% by mass, 9% by mass, 10% by mass, 12% by mass, 15% by mass, 17% by mass, 20% by mass, 25% by mass, and 30% by mass. In terms of preventing inconvenience such as precipitation, the upper limit of the preferred amount is 50% by mass, 40% by mass, 30% by mass, 25% by mass, 20% by mass, 18% by mass, 15% by mass, 13% by mass, and 10% by mass.
The above is a description of the compounds represented by general formula (i) and general formula (ii), which are essential components of the liquid crystal composition of the present invention. The liquid crystal composition according to the present invention may contain, as optional components, one or two or more selected from the group consisting of compounds represented by general formulae (1a) to (1c), compounds represented by general formulae (2a) to (2c), and compounds represented by general formula (iii) The optional components of the liquid crystal composition according to the present invention will be described below.
Preferably, the liquid crystal composition according to the present invention further contains one or two or more compounds selected from general formula (1a), general formula (1b), and general formula (1c) below.
In general formulae (1a) to (1c),
R11, R12, and R13 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms, wherein one methylene group or two or more non-adjacent methylene groups in these groups are optionally substituted with —O— or —S—, and one or two or more hydrogen atoms in these groups are optionally substituted with a fluorine atom or a chlorine atom,
M11, M12, M13, M14, M15, and M16 each independently represent any one of the following group (a), group (b), or group (d),
(a) a trans-1,4-cyclohexylene group (one methylene group or two or more non-adjacent methylene groups in this group are optionally substituted with —O— or —S—),
(b) a 1,4-phenylene group (one —CH═ or two or more non-adjacent —CH='s in this group are optionally substituted with —N═), a 3-fluoro-1,4-phenylene group, or a 3,5-difluoro-1,4-phenylene group, and
(d) a 1,4-cyclohexenylene group, a 1,4-bicyclo[2.2.2]octylene group, a piperidine-2,5-diyl group, a naphthalene-2,6-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, or a decahydronaphthalene-2,6-diyl group,
one or two or more hydrogen atoms in the group (a), the group (b), or the group (d) are each optionally substituted with a cyano group, a fluorine atom, a chlorine atom, a trifluoromethyl group, or a trifluoromethoxy group,
L11, L12, L13, L14, L15, and L16 each independently represent a single bond, —COO—, —OCO—, —CH2CH2—, —(CH2)4—, —OCH2—, —CH2O—, —OCF2—, —N═N—, —CF2O—, or —C≡C—,
p, q, and s each independently represent 0, 1, or 2,
a plurality of M12s, M14s, M16s, L11s, L13s, and/or L15s, if present, may be the same or different,
X11, X12, X13, X14, X15, X16, and X17 each independently represent a hydrogen atom or a fluorine atom, and
Y11, Y12, and Y13 each independently represent a fluorine atom, a chlorine atom, a cyano group (—CN), a thiocyanato group (—SCN), a cyanato group (—OCN), —C≡C—CN, a trifluoromethoxy group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a difluoromethoxy group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms, wherein one methylene group or two or more non-adjacent methylene groups in these groups are optionally substituted with —O— or —S—, and one or two or more hydrogen atoms in these groups are optionally substituted with a fluorine atom or a chlorine atom,
provided that the compound represented by general formula (i) is excluded from the compounds represented by (1a), (1b), and (1c).
The liquid crystal composition according to the present invention preferably contains at least one or two or more compounds selected from the group consisting of the compounds represented by general formulae (1a) to (1c), and particularly preferably contains two to eight compounds. In the liquid crystal composition according to the present invention, the lower limit of the amount (100% by mass of the entire liquid crystal composition) of at least one or two or more liquid crystal compounds selected from the group consisting of the compounds represented by general formula (1a) to general formula (1c) is preferably 1% by mass, more preferably 3% by mass, and even more preferably 5% by mass. In the liquid crystal composition according to the present invention, the upper limit of the amount (100% by mass of the entire liquid crystal composition) of at least one or two or more liquid crystal compounds selected from the group consisting of the compounds represented by general formula (1a) to general formula (1c) is 60% by mass, preferably 50% by mass, preferably 40% by mass, even more preferably 30% by mass.
The liquid crystal composition according to the present invention more preferably contains at least one or two or more compounds selected from the group consisting of the compounds represented by general formula (1a) or (1b), and even more preferably contains at least one or two or more compounds selected from the group consisting of the compounds represented by general formula (1a).
The lower limit of the preferred amount (% by mass) of the compound represented by formula (1a) in the total amount of the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 25%, 30%, and 35%. In terms of preventing inconvenience such as precipitation, the upper limit of the preferred amount is 35%, 30%, 25%, 20%, 15%, 10%, 5%, and 3%.
As a preferred form of the compounds of general formula (1a), compounds represented by general formula (1a.1) to general formula (1a.59) below are preferred.
In general formulae (1a.1) to (1a.59), R11a represents an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, and an alkenyloxy group having 2 to 12 carbon atoms.
R11c represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms,
X11a to Xiic, Xiig, and Xiih each independently represent a hydrogen atom or a fluorine atom, and
Z11a, Z11b, Z11c, and Z11d each independently represent —OCH2—, —CH2O—, —C2H4—, —C4H8—, —COO—, —OCO—, —CH═CH—, —CF═CF—, —CF2O—, —OCF2—, —CF2CF2—, —C≡C—, or a single bond.
Among the compounds represented by general formulae (1a.1) to (1a.59), (1a.1) to (1a.24), (1a.26), and (1a.35) to (1a.54) are preferred.
Specific examples of the compounds of general formula (1a) include compounds represented by structural formulae (1a.11.1) to (1a.48.5) below.
Among the compounds represented by structural formulae (1a.11.1) to (1a.48.5), (1a.11.2) to (1a.11.5), (1a.18.2) to (1a.18.5), (1a.24.12) to (1a.24.15), (1a.28.2) to (1a.28.5), (1a.28.7) to (1a.28.10), (1a.35.3), (1a.36.3), (1a.47.3), and (1a.48.3) are preferred.
As a preferred form of general formula (1a), the compound represented by general formula (1a-1) is preferred. The compound represented by general formula (1a-1) can be used to produce a composition having a liquid crystal phase over a wide temperature range, low viscosity, good solubility at low temperatures, high specific resistance and voltage retention, and stability against heat and light, while achieving a high Δn.
(In the formula, Y11, X11, and X12 respectively have the same meaning as Y11, X11, and X12 in general formula (1a),
R1a1 represents an alkynyl group having 2 to 12 carbon atoms, wherein one or two or more non-adjacent —CH2-'s in the alkynyl group are each independently optionally substituted with —CH═CH—, —C≡C—, —O—, —CO—, —COO—, or —OCO—, and one or two or more hydrogen atoms in R1a1 are each independently optionally substituted with a fluorine atom,
X13 to X15 each independently represent a hydrogen atom or a fluorine atom, wherein X11 and X13 do not simultaneously represent a fluorine atom, and X14 and X15 do not simultaneously represent a fluorine atom,
A1a1 has the same meaning as M11 in general formula (1a),
Z1a1 has the same meaning as L11 in general formula (1a), and
m1a1 represents 0 or 1.)
The compounds represented by formula (1a-1) may be used singly or in combination of two or more.
The lower limit of the amount (% by mass) of the compound represented by general formula (1a-1) in the total amount of the liquid crystal composition of the present invention is preferably 1 mass %, preferably 2%, preferably 5%, preferably 7%, preferably 9%, preferably 10%, preferably 12%, preferably 15%, preferably 17%, and preferably 20%. In terms of preventing inconvenience such as precipitation, the upper limit is preferably 50%, preferably 40%, preferably 30%, preferably 25%, preferably 20%, preferably 18%, preferably 15%, preferably 13%, and preferably 10%.
In general formula (1a-1), R1a1 is preferably an alkynyl group having 1 to 8 carbon atoms and preferably selected from groups represented by any of formulae (R11) to (R15). (The black circle in each formula represents a carbon atom in a ring structure.)
(R13) and (R14) are particularly preferred.
In general formula (1a-1), Y11 is preferably a fluorine atom, a cyano group, a trifluoromethyl group, or a trifluoromethoxy group when the compound represented by general formula (1a-1) is what is called a p-type compound with a positive Δε, and preferably a fluorine atom or a cyano group in terms of improving Δε.
When the compound represented by general formula (1a-1) is what is called a nonpolar compound in which Δε is almost zero, Y11 represents an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms, wherein one methylene group or two or more non-adjacent methylene groups in these groups preferably represent a group optionally substituted with —O— or —S—.
A1a1 is preferably aromatic when a higher Δn is required, preferably aliphatic in order to improve the response speed, preferably each independently represents a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group, a 3-fluoro-1,4-phenylene group, a 3,5-difluoro-1,4-phenylene group, a 1,4-cyclohexenylene group, a 1,4-bicyclo[2.2.2]octylene group, a piperidine-1,4-diyl group, a naphthalene-2,6-diyl group, a decahydronaphthalene-2,6-diyl group, or a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, and more preferably represents the following structure,
more preferably represents a trans-1,4-cyclohexylene group or a 1,4-phenylene group.
Z1a1 is preferably a single bond.
m1a1 is preferably 0 when the solubility in the liquid crystal composition is important, and preferably 1 when Δn and Tni are important.
X11 to X14 are all hydrogen atoms, or preferably one is a fluorine atom and the rest are hydrogen atoms, and preferably X14 is a fluorine atom and the rest are hydrogen atoms.
The compounds represented by general formula (1a-1) are preferably compounds represented by general formula (1a-11) to general formula (1a-34) below.
Preferably, the liquid crystal composition according to the present invention further contains one or two or more compounds represented by general formulae (2a) to (2c) below.
In formulae (2a) to (2c),
R2a and R2b each independently represent an alkyl group having 1 to 12 carbon atoms and may be linear or have a methyl or ethyl branch, and may have a 3 to 6 membered ring structure, wherein arbitrary —CH2— present in the group is optionally substituted with —O—, —S—, —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF—, or —C≡C—, and an arbitrary hydrogen atom in the group is optionally substituted with a fluorine atom or a trifluoromethoxy group,
the ring A, the ring B, the ring C, and the ring D each independently represent a trans-1,4-cyclohexylene group, a trans-decahydronaphthalene-trans-2,6-diyl group, a 1,4-phenylene group optionally substituted with one or two fluorine atoms or methyl groups, a naphthalene-2,6-diyl group optionally substituted with one or more fluorine atoms, a tetrahydronaphthalene-2,6-diyl group optionally substituted with one or two fluorine atoms, a 1,4-cyclohexenylene group optionally substituted with one or two fluorine atoms, a 1,3-dioxane-trans-2,5-diyl group, a pyrimidine-2,5-diyl group, or a pyridine-2,5-diyl group,
L2a, L2b, and L2c are each an independent linking group and represent a single bond, an ethylene group (—CH2CH2—), a 1,2-propylene group (—CH(CH3) CH2— and —CH2CH(CH3)—), a 1,4-butylene group, —COO—, —OCO—, —OCF2—, —CF2O, —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF—, —C≡C—, or —CH═N—N═CH—.
The liquid crystal composition according to the present invention preferably contains at least one compound selected from the group consisting of the compounds represented by general formulae (2a) to (2c), and particularly preferably contains two to eight compounds. In the liquid crystal composition according to the present invention, the lower limit of the amount (100% by mass of the entire liquid crystal composition) of at least one or two or more liquid crystal compounds selected from the group consisting of the compounds represented by general formula (2a) to general formula (2c) is preferably 0% by mass, more preferably 3% by mass, and even more preferably 5% by mass. In the liquid crystal composition according to the present invention, the upper limit of the amount (100% by mass of the entire liquid crystal composition) of at least one or two or more liquid crystal compounds selected from the group consisting of the compounds represented by general formula (2a) to general formula (2c) is 50% by mass, preferably 45% by mass, preferably 38% by mass, and even more preferably 25% by mass.
The liquid crystal composition according to the present invention more preferably contains at least one or two or more compounds selected from the group consisting of the compounds represented by general formula (2a) or (2b), and even more preferably contains one or two or more compounds selected from the group consisting of the compounds represented by general formula (2a).
The lower limit of the preferred amount (% by mass) of the compound represented by formula (2a) in the total amount of the liquid crystal composition of the present invention is 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, and 3%. In terms of preventing inconvenience such as precipitation, the upper limit of the preferred amount is 45%, 35%, 25% 15%, 10%, 8%, and 5%.
Examples of a preferred form of the compounds represented by general formulae (2a) to (2c) include compounds represented by general formulae (2a-1) to (2a-28) below.
In general formulae (2a-1) to (2a-29), R2a and R2b each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkenyloxy group having 2 to 8 carbon atoms, or a thioalkoxy group having 1 to 8 carbon atoms, and the ring E, the ring F, the ring G, and the ring H each independently represent any one of formulae (a1) to (a25).
Among the compounds of general formulae (2a-1) to (2a-29), (2a-1) to (2a-3), (2a-5), (2a-8) to (2a-10), and (2a-12) are preferred.
Specific examples of the compounds of general formula (2a) according to the present invention include compounds represented by structural formulae (2a-5.1) to (2a-5.13) and (2a-12.1) to (2a-12.8) below.
Among the compounds represented by structural formulae (2a-5.1) to (2a-5.13) and (2a-12.1) to (2a-12.8), (2a-5.2) to (2a-5.5), (2a-5.11) to (2a-5.13), and (2a-12.1) to (2a-12.4) are preferred.
Preferably, the liquid crystal composition according to the present invention further contains at least one compound selected from the group consisting of compounds represented by general formula (iii).
In general formula (iii),
Riii1 represents a linear or branched alkyl group or alkyl halide group having 1 to 40 carbon atoms, wherein a methylene group or an alkylene halide group containing one secondary carbon atom in these groups is optionally substituted with —O—, —CH═CH—, or —C≡C— such that oxygen atoms are not directly adjacent to each other,
miii1 represents an integer of 0, 1, or 2,
Aiii1 to Aiii3 each independently represent any one of the following groups (a) to (c),
(a) a 1,4-cyclohexylene group (one methylene group or two or more non-adjacent methylene groups in this group are optionally substituted with —O— or —S—),
(b) a 1,4-phenylene group (one —CH═ or two or more non-adjacent —CH='s in this group are optionally substituted with —N═),
(c) a naphthalene-2,6-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, or a decahydronaphthalene-2,6-diyl group (one —CH═ or two or more non-adjacent —CH='s in the naphthalene-2,6-diyl group or the 1,2,3,4-tetrahydronaphthalene-2,6-diyl group are optionally substituted with —N═),
hydrogen atoms in the groups (a) to (c) are each independently optionally substituted with a fluorine atom, a chlorine atom, or a linear or branched alkyl group or alkyl halide group having 1 to 10 carbon atoms,
Ziii1 and Ziii2 each independently represent a single bond, —C≡C—, —CH═CH—, —CF═CF—, or —C(Riiia)═N—N═C(Riiib)—, wherein Riiia and Riiib each independently represent a hydrogen atom, a halogen atom, or a linear or branched alkyl group or alkyl halide group having 1 to 10 carbon atoms, and
a plurality of Aiii1s and Ziii1s present when miii1 is 2 may be the same or different.
In general formula (iii), Riii1 preferably represents a linear alkyl group or an alkyl halide group having 1 to 11 carbon atoms, wherein a methylene group or an alkylene halide group containing one secondary carbon atom in these groups is optionally substituted with —O—, —CH═CH—, or —C≡C— such that oxygen atoms are not directly adjacent to each other.
In general formula (iii), Aiii1 to Aiii3 are preferably each independently a trans-1,4-cyclohexylene group or a 1,4-phenylene group optionally substituted with a fluorine atom, a chlorine atom, or a linear alkyl group or alkyl halide group having 1 to 10 carbon atoms. Examples of Aiii1 to Aiii3 similarly include divalent cyclic groups represented by formulae (a1) to (a25) exemplified for Ai1 of general formula (i). Specifically, Aiii1 to Aiii3 are each independently preferably formulae (a1) to (a3), (a5) to (a6), (a9) to (a10), (a12) to (a25), more preferably (a1) to (a3) and (a12) to (a25), and even more preferably (a1) to (a3) and (a12) to (a18).
In general formula (iii), Ziii1 and Ziii2 preferably each independently represent a single bond, —C≡C—, —CH═CH—, —CF═CF—, or —C(Riiia)═N—N═C(Riiib)—.
Here, Riiia and Riiib preferably each independently represent a hydrogen atom, a halogen atom, or a linear alkyl group or alkyl halide group having 1 to 10 carbon atoms.
In general formula (iii), Ziii1 and Ziii2 are more preferably each independently a single bond or —C≡C—. More preferably, a molecule of the compound represented by general formula (iii) has at least one —C≡C—. That is, in general formula (iii), preferably, at least one of Ziii2 and 0 or more and 2 or less Ziii1 represent —C≡C—.
In general formula (iii), miii1 preferably represents an integer of 0, 1, or 2. A plurality of Aiii1 and Ziii1 present when miii1 is 2 may be the same or different.
The liquid crystal composition according to the present invention preferably contains at least one compound represented by (iii) and particularly preferably contains two to eight compounds.
The lower limit of the preferred amount (% by mass) of the compound represented by general formula (iii) in the total amount of the liquid crystal composition of the present invention is 1.7% by mass, 2% by mass, 4% by mass, 4.3% by mass, 5% by mass, 5.7% by mass, and 6% by mass. In terms of preventing inconvenience such as precipitation, the upper limit of the preferred amount is 23% by mass, 20% by mass, 18% by mass, 14% by mass, 13% by mass, 10% by mass, 8% by mass, and 5% by mass. In the liquid crystal composition of the present invention, the preferred amount of the compound represented by general formula (iii) is 2 to 20% by mass, more preferably 4 to 15% by mass, and particularly preferably 6 to 12% by mass.
Examples of specific structures of general formula (iii) include compounds represented by general formulae (iii.1) to (iii.6) below.
In general formulae (iii.1) to (iii.7), R35 represents an alkyl group having 1 to 8 carbon atoms, or an alkoxyl group having 1 to 8 carbon atoms, or an alkenyl group having 2 to 8 carbon atoms, R36 represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and Xiii1 to Xiii6 each independently represent a hydrogen atom, a fluorine atom, or a chlorine atom.
More specifically, the compounds represented by general formulae (iii.1) to (iii.7) are preferably compounds represented by structural formulae (iii.a) to (iii.e) below.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (ii) is preferably 10 to 85%, preferably 13 to 80%, and preferably 15 to 70% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (iii) is preferably 13 to 88%, preferably 16 to 85%, and preferably 18 to 73% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (ii) and general formula (1a) is preferably 13 to 88%, preferably 16 to 85%, and preferably 18 to 73% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (ii) and general formula (2a) is preferably 13 to 88%, preferably 16 to 85%, and preferably 18 to 73% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (ii) and general formula (2b) is preferably 13 to 88%, preferably 16 to 85%, and preferably 18 to 73% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (ii) and general formula (2c) is preferably 13 to 88%, preferably 16 to 85%, and preferably 18 to 73% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (iii) and general formula (1a) is preferably 30 to 93%, preferably 35 to 88%, and preferably 40 to 85% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (iii) and general formula (2a) is preferably 30 to 93%, preferably 35 to 88%, and preferably 40 to 85% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (iii) and general formula (2b) is preferably 30 to 93%, preferably 35 to 88%, and preferably 40 to 85% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (iii) and general formula (2c) is preferably 30 to 93%, preferably 35 to 88%, and preferably 40 to 85% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (ii), the compound represented by general formula (1a), and the compound represented by general formula (2a) is preferably 30 to 89%, preferably 35 to 93%, and preferably 40 to 85% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (ii), the compound represented by general formula (1a), and the compounds represented by general formulae (2a) to (2b) is preferably 30 to 93%, preferably 35 to 88%, and preferably 40 to 85% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (ii), the compound represented by general formula (1a), and the compounds represented by general formulae (2a) to (2c) is preferably 30 to 93%, preferably 35 to 88%, and preferably 40 to 85% of the entire liquid crystal composition.
In the liquid crystal composition according to the present invention, the total amount (% by mass) of the compounds represented by general formulae (i) to (iii), the compound represented by general formula (1a), and the compounds represented by general formulae (2a) to (2c) is preferably 33 to 96%, preferably 38 to 91%, and preferably 43 to 88% of the entire liquid crystal composition.
The liquid crystal composition according to the present invention may contain, in addition to the liquid crystal compounds described above, additives such as a known stabilizer, a known polymerizable liquid crystal compound, or a polymerized compound, as necessary depending on the manner of use.
Examples of the stabilizer include hydroquinones, hydroquinone monoalkyl ethers, tertiary butyl catechols, pyrogallols, thiophenols, nitro compounds, β-naphthylamines, β-naphthols, nitroso compounds, hindered phenols, and hindered amines. When the stabilizer is used, the amount added is preferably in the range of 0.005 to 1% by mass of the liquid crystal composition, even more preferably 0.02 to 0.5% by mass, and particularly preferably 0.03 to 0.1% by mass.
The liquid crystal phase upper limit temperature (TNI) of a liquid crystal composition is the temperature at which the liquid crystal composition exhibits a phase transition from the nematic phase to the isotropic phase. As TNI increases, the nematic phase can be retained even at higher temperatures, and a wider drive temperature range can be ensured. TNI is preferably 120° C. or higher, preferably 120 to 200° C., and preferably 130 to 180° C.
The liquid crystal composition according to the present invention preferably has a Δn (refractive index anisotropy) of 0.3 or higher at 25° C. and 589.0 nm, preferably 0.3 to 0.60, preferably 0.33 to 0.55, preferably 0.35 to 0.50. Δn in the visible light region correlates with Δε in the tens of GHz band, and as Δn increases, change in dielectric constant in the GHz band can be increased. Therefore, when the liquid crystal composition has Δn of 0.3 or higher at 589.0 nm, the change in dielectric constant in the GHz band can be increased and therefore the liquid crystal composition is suitable for antennas.
Here, the relationship between the phase difference Re, the thickness d (cell gap) of the liquid crystal layer, and Δn is expressed by an equation: Δn=Re/d. In the present description, Δn is obtained from a phase difference measurement device. More specifically, a sample of the liquid crystal composition of the present invention is injected into a glass cell with a polyimide alignment film, and the in-plane retardation (phase difference Re) at a measurement temperature of 25° C. and 589 nm is measured with a retardation film and optical material inspection system RETS-100 (Otsuka Electronics Co., Ltd.). A glass cell with a cell gap of 3.0 μm between glass substrates was used, in which the rubbing direction of the polyimide alignment film is parallel.
The ne and no of the liquid crystal composition may be measured with an Abbe refractometer to calculate Δn.
The Δε (dielectric constant anisotropy) of the liquid crystal composition according to the present invention at 25° C. and 1 kHz is preferably 12 or higher, preferably 12 to 30, preferably 13 to 25, and preferably 14 to 20.
A liquid crystal element including the liquid crystal composition according to the present invention, more specifically, a liquid crystal element, a sensor, a liquid crystal lens, an optical communication device, and an antenna will be described below.
The liquid crystal element according to the present invention includes the liquid crystal composition described above and is preferably driven by an active matrix system or a passive matrix system.
The liquid crystal element according to the present invention is preferably a liquid crystal element in which the dielectric constant is reversely switched by reversibly changing the orientation direction of liquid crystal molecules of the liquid crystal composition described above.
The sensor according to the present invention includes the liquid crystal composition described above. Examples of embodiments thereof include ranging sensors using electromagnetic waves, visible light, or infrared light, infrared sensors using temperature change, temperature sensors using reflected light wavelength change caused by pitch change of cholesteric liquid crystal, pressure sensors using reflected light wavelength change, UV sensors using reflected light wavelength change caused by compositional change, electrical sensors using temperature change caused by voltage or current, radiation sensors using temperature change involved with track of radiation particles, ultrasonic sensors using liquid crystal molecules' arrangement change caused by mechanical vibration of ultrasonic waves, and electromagnetic field sensors using reflected light wavelength change caused by temperature change or liquid crystal molecules' arrangement change caused by electric fields.
The ranging sensors are preferably for light detection and ranging (LiDAR) using a light source.
Preferred LiDAR applications are satellites, aircrafts, unmanned aerial vehicles (drones), automobiles, railroads, and ships.
For automobile applications, self-driving automobile applications are particularly preferred.
The light source is preferably an LED or a laser, and preferably a laser.
Light used for LiDAR is preferably infrared light and preferably has a wavelength of 800 to 2,000 nm.
An infrared laser with a wavelength of 905 nm or 1,550 nm is particularly preferred.
An infrared laser with 905 nm is preferred when the cost of photodetectors used and sensitivity in all weathers are important. An infrared laser with 1,550 nm is preferred when safety of human vision is important.
The liquid crystal composition according to present invention exhibits a high Δn and therefore can provide sensors with high phase modulation power in the visible light, infrared light, and electromagnetic wave regions and with high detection sensitivity.
The liquid crystal lens according to the present invention includes the liquid crystal composition described above and, for example, according to an embodiment, includes a first transparent electrode layer, a second transparent electrode layer, a liquid crystal layer containing the liquid crystal composition described above between the first transparent electrode layer and the second transparent electrode layer, an insulating layer between the second transparent electrode layer and the liquid crystal layer, and a high resistance layer between the insulating layer and the liquid crystal layer. The liquid crystal lens according to the present invention is used, for example, as a 2D/3D switchable lens and a focusing lens for cameras.
The optical communication device according to the present invention includes the liquid crystal composition described above. Examples thereof include, as one of its embodiments, a liquid crystal on silicon (LCOS) including a liquid crystal layer in which liquid crystals forming a plurality of pixels are arranged in two dimensions on a reflective layer (electrode). The optical communication device according to the present invention is used, for example, as a spatial phase modulator.
The antenna according to the present invention includes the liquid crystal composition described above.
More specifically, the antenna according to the present invention includes a first substrate having a plurality of slots, a second substrate facing the first substrate and having a power feed section, a first dielectric layer between the first substrate and the second substrate, a plurality of patch electrodes disposed corresponding to the slots, a third substrate having the patch electrodes, and a liquid crystal layer between the first substrate and the third substrate, in which the liquid crystal layer contains the liquid crystal composition described above.
The liquid crystal layer containing the liquid crystal compounds represented by general formulae (i) and (ii) can be used to provide an antenna having a high dielectric constant anisotropy Δε, a high refractive index anisotropy Δn, a wide nematic liquid crystal temperature range, stability at room temperature, and high reliability against external stimuli such as heat. Thus, an antenna capable of greater phase control over electromagnetic waves in the microwave or millimeter wave range can be provided.
The antenna according to the present invention will be described below with reference to the drawings.
As illustrated in
The term “antenna” as used herein includes the antenna unit 1 or the antenna assembly 11 having a plurality of antenna units 1 connected together.
Preferably, the antenna according to the present invention operates in the Ka-band frequencies or K-band frequencies or the Ku-band frequencies used for satellite communications.
An exemplary embodiment of the components of the antenna unit 1 is illustrated in
The control board 4 is provided with a transmitter and/or a receiver. The transmitter has a mechanism to transmit information from a signal source, such as sound or image data, in the form of radio waves, for example, after voice encoding, image encoding, or the like by an information source encoding process, error correcting encoding by a transmission line encoding process, and modulation. On the other hand, the receiver has a mechanism to modulate incoming radio waves, correct errors by a transmission line decoding process, perform, for example, voice decoding or image decoding by an information source decoding process, and convert the decoded signals into information such as voice or image data. The control board 4 is a known microcomputer composed of a CPU, a RAM, a ROM, and the like and centrally controls the operation of each part of the antenna body 1, the transmitter and/or the receiver. The CPU or the ROM of the control board 4 reads various programs stored in advance into the RAM and executes the programs to perform predetermined processes. The control board 4 has functions such as a memory to store various setting information or control programs, a computing unit to perform various computations related to the amount and the direction of voltage applied to the liquid crystal layer in the antenna body 1, various computations related to transmission of radio waves, and/or various computations related to reception of radio waves, and a detector to detect received or transmitted radio waves or detect a voltage applied to the liquid crystal layer.
In
The configuration of the antenna body 10 will be described below with reference to
As illustrated in
The slot array section 6 is an antenna section having notches (hereinafter slots 8) formed in the disc-shaped conductor Q as radiating elements (or incidence elements). The slot array section 6 has the slots 8 and the power feed section 12 provided at the center of the disc-shaped conductor Q. In general, the slot array section 6 has a mechanism directly excited at the distal end of a transmission line or excited through a cavity on the back of the slot. The slot array section 6 can be used for power feeding to the patch antenna through the slot from an antenna with a ground plate, a microstrip line, or the like. In
In the present description, two slots 8 are referred to as slot pair 8, one slot 8 is simply referred to as slot 8, and slot and slot pair are collectively referred to as slot (pair) 8.
A plurality of slot pairs 8 are formed in a spiral shape from the center of the disc-shaped conductor substrate P to the radially outer side. The slot pairs 8 are formed on the surface of the disc-shaped substrate such that the distance between the slot pairs 8 adjacent along the spiral is constant. This configuration allows the phases to be matched in front of the slot array section 6 to enhance electromagnetic fields, thereby forming a pencil beam in front.
In
The power feed section 12 in the present invention has the function of receiving electromagnetic waves and/or radiating electromagnetic waves. The power feed section 12 in the present invention may be any section that transmits to the receiver high-frequency power generated by capturing radio waves with the patches 9 that are radiating elements or incidence elements, or any section that connect the radiating elements to the power feed line for supplying high-frequency power. Known power feeders and power feed lines can be used.
As illustrated in
In
In general, the method of feeding the radiating element (for example, patch 9) of the patch array section 7 using a common transmission line such as coaxial line or a planar transmission line can be classified mainly into two types: direct coupling feeding and electromagnetic coupling feeding. Thus, the feeding method in the present invention includes two methods: direct coupling feeding in which a transmission path is directly connected to the patch 9 (radiating element) to excite the radiating element; and electromagnetic coupling feeding in which the patch electrode (radiating element) is excited by an electromagnetic field produced on the periphery of an open-ended or short-circuited power feed line, rather than directly connecting the transmission path to the patch electrode (radiating element). In the present invention, a manner of the electromagnetic coupling feeding is indicated.
In the present embodiment, since the power feed line by the (coaxial) power feed section 12 is open-ended, a current standing wave is generated such that the terminal of the power feed line coincides with a node. Then, a magnetic field surrounding the power feed line ((coaxial) power feed section 12) is produced, and this magnetic field is incident on the slot 8 to excite the slot (pair) 8. The magnetic field produced by the excitation of the slot (pair) 8 is then incident on the patch 9 to excite the patch 9. It is preferable that the slot (pair) 8 is formed at a position where the magnetic field produced from the power feed line ((coaxial) power feed section 12) is strongest (an antinode of the current standing wave), because the excitation intensity is largest when the magnetic field incident on the slot 8 is strongest.
A preferred embodiment of the antenna according to the present invention is a combination of a radial line slot array and a patch antenna array.
An embodiment of the antenna body 10 will now be described with reference to
As illustrated in
As used herein “the patch(es) 9 correspond to (respective) slot pair(s) 8” means that the projected plane of the patch 9 projected perpendicularly to the main surface of the second substrate 14 overlaps with the slot (pair) 8, as explained with reference to
The first substrate 13, the second substrate 14, and the third substrate 15 are preferably disc bodies having the same area.
In
On the other hand, in reception of an incoming radio wave, based on the reciprocity theorem of transmission and reception, after the patch 9 receives an incoming radio wave, the incoming wave is propagated to the power feed section 12 via the slot (pair) 8 provided directly below the patch 9, in a reverse manner of the above.
Circularly polarized waves are radio waves in which, unlike linearly polarized waves, the electric field direction rotates over time, and classified into right-circularly-polarized waves for use in GPS or ETC and left-circularly-polarized waves for use in satellite radio broadcasting and the like. The antenna according to the present invention can receive any one of the polarized waves.
The orientation direction of liquid crystal molecules in the liquid crystal layer 16 can be changed by applying a voltage to the liquid crystal layer 16 between the patches 9 and the first substrate 13. As a result, the dielectric constant of the liquid crystal layer 16 changes, and the capacitance of the slot (pair) 8 changes accordingly. Consequently, the reactance and the resonance frequency of the slot (pair) 8 can be controlled. In other words, since the reactance and the resonance frequency of the slot 8 can be adjusted by controlling the dielectric constant of the liquid crystal layer 16, power feeding to each patch 9 can be controlled by adjusting the excitation of the slot (pair) 8 and the patch 9. Thus, radiation radio waves can be adjusted through the liquid crystal layer 16. For this, for example, a voltage application adjuster for adjusting a voltage to be applied to the liquid crystal layer 16, such as a TFT, may be provided. Changing the orientation direction of liquid crystal molecules in the liquid crystal layer 16 changes the refractive index, resulting in phase shifting of the electromagnetic waves transmitted through the liquid crystal layer 16. Consequently, phased array control can be implemented.
The first substrate 13 and the second substrate 14 can be formed of any material that is a conductor such as copper. The material of the third substrate 15 is not limited and can be selected from known materials such as glass substrates, acrylic substrates, ceramic (alumina), silicon, and glass cloth Teflon (registered trademark) (PTFE), depending on the manner of use. The material of the first dielectric layer 17 can be selected as appropriate from known materials depending on the desired dielectric constant and may be a vacuum. The patch 9 may be formed of any material that is a conductor such as copper or silver.
Another embodiment of the antenna body 10 will now be described with reference to
In
As illustrated in
On the other hand, in reception of an incoming radio wave, similarly, after the patch 9 receives an incoming radio wave, the incoming radio wave propagates to the power feed section 12 via the slot (pair) 8 provided directly below the patch 9.
Yet another embodiment of the antenna body 10 will now be described with reference to
As illustrated in
An embodiment of the antenna body 10 will now be described with reference to
As illustrated in
Although not illustrated in
The sealed region 20 in the present embodiment will now be described with reference to
As illustrated in
In the present embodiment, the seal walls 24 may be formed of a known insulator or the like. The buffer layer 22 may be formed of a known dielectric material or the like.
Although not illustrated in
In this case, an alignment film may be provided for fixing the orientation direction of liquid crystal molecules forming the liquid crystal layer 16 in each sealed region 20. As the alignment film, a homeotropic alignment film that facilitates vertical orientation of liquid crystal molecules or a homogeneous alignment film that facilitates horizontal orientation of liquid crystal molecules may be provided between the first substrate 13 and the liquid crystal layer 16.
The voltage applied to the liquid crystal layer 16 between the patch 9 and the first substrate 13 may be modulated in order to tune the liquid crystal layer 16. For example, as described above, the voltage applied to the liquid crystal layer 16 is controlled using the active system, whereby the capacitance of the slot 8 is changed. Consequently, the reactance and the resonance frequency of the slot 8 can be controlled. The resonance frequency of the slot 8 is correlated with energy radiating from the radio wave propagating on the line. The resonance frequency of the slot 8 is therefore adjusted so that the slot 8 is not substantially coupled to the cylindrical wave energy from the power feed section 12, or is coupled to the cylindrical wave energy and radiates the energy into free space. Such control of the reactance and resonance frequency of the slot 8 can be performed in each of the sealed regions 20. In other words, power feeding to the patch 9 in each sealed region 20 can be controlled by the TFT by controlling the dielectric constant of the liquid crystal layer 16. Thus, patches 9 to transmit radio waves and patches not to transmit radio waves can be controlled, so that transmission and reception of radiated radio waves can be adjusted through the liquid crystal layer 16.
The present invention will be described in more detail below with examples, but the present invention is not intended to be limited by the following examples.
In a nitrogen atmosphere, 33.7 g of the compound represented by formula (I-1-1), 0.5 g of copper(I) iodide, 67 mL of triethylamine, 202 mL of N,N-dimethylformamide, and 0.9 g of bis(triphenylphosphine)palladium(II) dichloride were added to a reaction vessel. At 80° C., a solution of 20.0 g of the compound represented by formula (I-1-2) dissolved in 20 mL of N,N-dimethylformamide was added dropwise, and the mixture was heated and stirred for 6 hours. The reaction solution was cooled and poured into water and extracted with toluene. The organic layer was washed sequentially with 5% hydrochloric acid, water, and salt water, and purified by column chromatography (silica gel, dichloromethane/hexane) to yield 20.6 g of the compound represented by formula (I-1-3).
In a nitrogen atmosphere, 18.6 g of the compound represented by formula (I-1-3) and 186 mL of tetrahydrofuran were added to a reaction vessel. At −70° C., 84.4 mL of a sec-butyllithium (1.05 M)/cyclohexane-hexane solution was added dropwise, and the mixture was stirred for 1 hour. At −65° C., a solution of 22.5 g of iodine dissolved in 68 mL of tetrahydrofuran was added dropwise, and the mixture was stirred for 2 hours. The temperature was gradually increased to room temperature. Water and a sodium hydrogen sulfite solution were added dropwise, and the solution was extracted with toluene. The organic layer was washed sequentially with water and salt water, and purified by column chromatography (silica gel, hexane) and recrystallization (methanol) to yield 13.9 g of the compound represented by formula (I-1-4).
In a nitrogen atmosphere, 12.9 g of the compound represented by formula (I-1-4), 10.4 g of bis(pinacolato)diboron, 10.1 g of potassium acetate, and 104 mL of dimethyl sulfoxide were added to a reaction vessel. At 85° C., 0.5 g of [1,1′-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane adduct was added, and the mixture was heated and stirred for 5 hours. The reaction solution was cooled and poured into water and extracted with toluene. The organic layer was washed sequentially with water and salt water, and purified by column chromatography (alumina, toluene) to yield 12.8 g of the compound represented by formula (I-1-5).
In a nitrogen atmosphere, 3.5 g of the compound represented by formula (I-1-6), 3.4 g of potassium carbonate, 28 mL of toluene, 14 mL of ethanol, 14 mL of water, and 0.2 g of dichlorobis[di-t-butyl(p-dimethylaminophenyl)phosphino]palladium(II) were added to a reaction vessel. With heating and refluxing, a solution of 6.1 g of the compound represented by formula (I-1-5) dissolved in 12 mL of toluene and 6 mL of ethanol was added dropwise, and the mixture was heated and refluxed for 5 hours. The reaction solution was poured into water and extracted with toluene. The organic layer was washed sequentially with water and salt water, and purified by column chromatography (silica gel, dichloromethane/hexane) and recrystallization (hexane) to yield 5.0 g of the compound represented by formula (I-1).
Phase transition temperature: C 79 N 134 I
1H-NMR (400 MHz, CHLOROFORM-D) δ 7.47-7.33 (m, 5H), 7.29-7.26 (d, 2H), 7.19 (d, J=8.2 Hz, 2H), 2.64 (t, J=7.8 Hz, 2H), 1.65-1.57 (m, 2H), 1.36 (td, J=14.9, 7.3 Hz, 2H), 0.94 (t, J=7.3 Hz, 3H)
MS (EI): m/z=389
The compound represented by formula (I-2) was produced by the same method as in Example 1, except that the compound represented by formula (I-1-6) was replaced by the compound represented by formula (I-2-2).
Phase transition temperature: C 76 N 183 I
MS (EI): m/z=371
The compound represented by formula (I-3) was produced by the same method as in Example 1, except that the compound represented by formula (I-1-2) was replaced by the compound represented by formula (I-3-2).
MS (EI): m/z=425
In a nitrogen atmosphere, 10.0 g of the compound represented by formula (II-1-1) and 100 mL of dichloromethane were added to a reaction vessel. At room temperature, a solution of 125 g of potassium peroxymonosulfate [KHSO5 (>approximately 45%)] dissolved in 200 mL of water was added dropwise, and the mixture was stirred for 15 hours at room temperature. The reaction solution was separated, and the organic layer was washed sequentially with 5% hydrochloric acid, water, and salt water. After the solvent was removed, the product was dissolved in 200 mL of acetic acid. At room temperature, 6.6 g of the compound represented by formula (II-1-2) was added, and the mixture was stirred for 15 hours. The precipitate was filtered and washed sequentially with acetic acid and water. By drying, 13.2 g of the compound represented by formula (II-1-3) was obtained.
The compound represented by formula (II-1-4) was produced by the method described in International Journal of Molecular Sciences, 2013, Vol. 14, No. 12, pp. 23257-23273. In a nitrogen atmosphere, 13.2 g of the compound represented by formula (II-1-3), 0.2 g of copper(I) iodide, 0.2 g of [1,1′-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane adduct, 26 mL of triethylamine, and 78 mL of N,N-dimethylformamide were added to a reaction vessel. With heating at 50° C., a solution of 6.7 g of the compound represented by formula (II-1-4) dissolved in 14 mL of N,N-dimethylformamide was added dropwise, and the mixture was heated and stirred for 8 hours. The reaction solution was poured into water and extracted with toluene. The organic layer was washed sequentially with 5% hydrochloric acid and salt water, and purified by column chromatography (silica gel, dichloromethane/hexane), activated carbon treatment, and recrystallization (acetone/hexane) to yield 10.2 g of the compound represented by formula (II-1).
MS (EI): m/z=398
The compound represented by formula (II-2) was produced by the same method as in Example 4 except that the compound represented by formula (II-1-1) was replaced by the compound represented by formula (II-2-1), that the compound represented by formula (II-1-2) was replaced by the compound represented by formula (II-2-2), and that the compound represented by formula (II-1-4) was replaced by the compound represented by formula (II-2-4).
MS (EI): m/z=402
Nematic liquid crystal compositions described in Examples were produced and various physical properties were measured. The compositions of the following Examples and Comparative Examples contain the compounds in the proportions listed in the tables, and the amount contained is indicated by “% by mass”. In the examples, the following abbreviations are used to describe the compounds.
In the following Examples, the trans forms are represented unless otherwise specified.
TNI (° C.): temperature at which the composition exhibits a transition from the nematic phase to the isotropic phase
<Refractive Index Anisotropy (Δn)>
Δn: refractive index anisotropy of the liquid crystal composition at 25° C. and 589 nm
The liquid crystal composition was injected into a glass cell with a polyimide alignment film, and the in-plane retardation (phase difference) at a measurement temperature of 25° C. and 589 nm was measured with a retardation film and optical material inspection system RETS-100 (Otsuka Electronics Co., Ltd.). A glass cell with a cell gap of 3.0 μm between glass substrates was used, in which the rubbing direction of the polyimide alignment film was parallel. The Δn of the liquid crystal composition was calculated from the formula: phase difference=thickness of liquid crystal layer (cell gap) x Δn.
Δε: dielectric constant anisotropy of the liquid crystal composition at 25° C.
The liquid crystal compounds listed in Tables 2 and 3 were prepared, nematic liquid crystal compositions were produced, and various physical properties were measured by the evaluation methods above.
The liquid crystal compounds listed in Tables 4 and 5 were prepared, nematic liquid crystal compositions were produced, and various physical properties were measured by the evaluation methods above.
The Δn in the visible light region correlates with Δε in the tens of GHz band, and as Δn increases, change in dielectric constant in the GHz band can be increased. Based on this, the evaluation results listed in Tables 2 to 5 demonstrated that the liquid crystal compositions of Examples 6 to 15 were suitable as liquid crystals for antennas. The evaluation results listed in Tables 2 to 5 demonstrated that Examples 6 to 15 have a higher Δn than Comparative Examples 3 to 4 and have a higher Tni and a higher Δε than Comparative Examples 1 to 2. It was demonstrated that Tni of Examples 6 to 15 is an equivalent or higher value than that of Comparative Examples 3 to 4 and is higher than that of Comparative Examples 1 to 2.
It was found that the liquid crystal compositions of Comparative Examples 1 to 4 are difficult to use as liquid crystals for antennas because Δn is low, or Δε is low so that great phase control over radio waves is impossible, or as does not reach a practical level.
Liquid crystal compositions were prepared and evaluated in the same manner as in Examples 6 to 15, and it was found that similar effects were achieved. The results are listed in Table 6.
The liquid crystal composition of the present invention can be used for crystal display elements, sensors, liquid crystal lenses, optical communication devices, and antennas.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-019699 | Feb 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/045958 | 12/10/2020 | WO |
