Light control device and imaging apparatus

Abstract

Provided is a light control device (10) comprising a plurality of liquid crystal light control layers (11), (14), and a retardation layer (13) disposed between the plurality of liquid crystal light control layers (11), (14), wherein the plurality of liquid crystal light control layers (11), (14) each includes a guest-host liquid crystal composition, and the softening temperature by thermal analysis measurement of the retardation layer (13) is 180°C or higher. Also provided is an imaging device apparatus (30) comprising the light control device.

Description

Light control device and imaging device

[0001] The present disclosure relates to a light control device and an imaging device.

[0002] In imaging devices such as cameras, a light control device called a neutral density filter, which uniformly reduces or changes the wavelength of light, is sometimes used to impart effects to captured images. Neutral density filters are also called ND filters (Neutral-density filters), neutral density filters, etc.

[0003] As an ND filter, a variable transmission filter using a guest-host liquid crystal and a polarization state changing device that is a half-wave plate is known (Patent Document 1).

[0004] Patent Document 1: International Publication No. 2017 / 172277

[0005] When an ND filter is used in an imaging device such as a camera, the ND filter may be discolored due to, for example, strong sunlight.

[0006] The present disclosure has been made in view of the above. An object of the present disclosure is to provide a light control device and an imaging device with improved light resistance.

[0007] Specific means for solving the problems include the following aspects. <1> A light control device comprising a plurality of liquid crystal light control layers and a retardation layer disposed between the plurality of liquid crystal light control layers, wherein each of the plurality of liquid crystal light control layers contains a guest-host liquid crystal composition, and the retardation layer has a softening temperature of 180°C or higher as measured by thermal analysis. <2> The light control device according to <1>, wherein the retardation layer contains a liquid crystal compound. <3> The light control device according to <2>, wherein the retardation layer contains a liquid crystal compound aligned by polymerization. <4> The light control device according to <2> or <3>, wherein the liquid crystal compound is a rod-shaped liquid crystal compound or a discotic liquid crystal compound. <5> The light control device according to any one of <1> to <4>, wherein the retardation layer has a softening temperature of 250°C or higher. <6> The light control device according to any one of <1> to <5>, wherein the retardation layer has an Re(550) of 100 nm to 300 nm and an Re(440) of 100 nm to 300 nm. <7> The light control device according to any one of <1> to <6>, wherein the retardation layer is a half-wave plate for 550 nm light and a half-wave plate for 440 nm light. <8> The light control device according to any one of <1> to <7>, further comprising a fixation layer that fixes the liquid crystal light control layer and the retardation layer, and having a first liquid crystal light control layer, a fixation layer, a retardation layer, a fixation layer, and a second liquid crystal light control layer in this order. <9> The light control device according to any one of <1> to <8>, wherein the retardation layer includes a plurality of optically anisotropic layers and a fixing layer that fixes the plurality of optically anisotropic layers, and has a first optically anisotropic layer, the fixing layer, and a second optically anisotropic layer in this order. <10> The light control device according to <9>, wherein the optically anisotropic layer is a quarter-wave plate for light of 550 nm and a quarter-wave plate for light of 440 nm. <11> An imaging device including the light control device according to any one of <1> to <10>.

[0008] According to the embodiments of the present disclosure, a light control device and an imaging device with improved light resistance are provided.

[0009] Fig. 1 is an explanatory diagram illustrating the configuration of an example of a light control device. Fig. 2 is an explanatory diagram illustrating the configuration of an example of a light control device. Fig. 3 is an explanatory diagram illustrating the arrangement of a light control device in a digital camera. Fig. 4 is an explanatory diagram illustrating the configuration of an optical laminate for forming a retardation layer.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments and can be implemented with appropriate modifications within the scope of the purpose of the present disclosure. Components indicated by the same reference numerals in each drawing are the same components. Explanations of duplicated components and reference numerals in each drawing may be omitted. The sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited thereto.

[0011] In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits. In the numerical ranges described in stages in the present disclosure, the upper or lower limit described in a certain numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit described in a certain numerical range may be replaced with a value shown in the examples.

[0012] In this specification, "orthogonal" does not mean strictly 90°, but means 90°±10°, preferably 90°±5°. Furthermore, "parallel" does not mean strictly 0°, but means 0°±10°, preferably 0°±5°. Furthermore, "45°" does not mean strictly 45°, but means 45°±10°, preferably 45°±5°. The same applies to 0°, 90°, etc., and do not mean strictly 0°, 90°, etc.

[0013] In the present disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved. In the present disclosure, the amount of each component in a composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified. In the present disclosure, a combination of two or more preferred aspects or forms is a more preferred aspect or form.

[0014] In the present disclosure, compounds that are not specified as substituted or unsubstituted may have any substituent within the scope that does not impair the effects of the present disclosure.

[0015] In this specification, unless otherwise specified, phase difference refers to in-plane retardation and is referred to as Re(λ). Here, Re(λ) represents the in-plane retardation at wavelength λ, and unless otherwise specified, wavelength λ is 550 nm. Furthermore, in this specification, retardation in the thickness direction at wavelength λ is referred to as Rth(λ). Unless otherwise specified, wavelength λ is 550 nm. Re(λ) and Rth(λ) can be values ​​measured at wavelength λ using, for example, an AxoScan OPMF-1 (manufactured by OptoScience). By inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d (μm)) into AxoScan, the following equations are calculated in the slow axis direction (°): Re(λ) = R0(λ) Rth(λ) = ((nx + ny) / 2 - nz) × d.

[0016] The light control device of the present disclosure includes a plurality of liquid crystal light control layers and a retardation layer disposed between the plurality of liquid crystal light control layers, wherein the liquid crystal light control layers each contain a guest-host liquid crystal composition, and the retardation layer has a softening temperature of 180° C. or higher as measured by thermal analysis. The imaging device of the present disclosure also includes the light control device of the present disclosure.

[0017] The background to the embodiment of the present disclosure will be explained. A guest-host liquid crystal type light control device is known in which a retardation layer is incorporated between two guest-host liquid crystal elements in order to improve dimming performance when a voltage is applied. For example, a technology is known in which a polymer retardation layer made of a polymer material such as a polycarbonate film is used as the retardation layer (see, for example, Patent Document 1).

[0018] When a light control device is used in a camera or the like, fading occurs due to sunlight or the like when used outdoors, and the performance of the light control device may be reduced. The present inventors have focused on the retardation layer as the cause of the fading, and have found that the fading of the light control device is related to softening of the retardation layer due to high temperatures caused by concentrated sunlight.

[0019] The present inventors have found that in a retardation layer of a light control device comprising a liquid crystal light control layer containing a guest-host liquid crystal composition and a retardation layer, discoloration of the light control device is unlikely to occur when the softening temperature measured by thermal analysis is 180°C or higher, and have completed an embodiment of the present disclosure.

[0020] Although the detailed mechanism by which the above-mentioned effect is obtained is unknown, the inventors speculate that when the retardation layer is heated, the molecular mobility is improved for some reason, the retardation performance is lost, and discoloration occurs, and that when the softening temperature of the retardation layer is equal to or higher than a specific temperature, the improvement in molecular mobility is suppressed, and therefore discoloration and the like are also suppressed.

[0021] According to the light control device of the present disclosure, it is possible to provide a light control device that suppresses fading and has improved light resistance, even when used for a long period of time outdoors on a sunny day. Because of the improved light resistance, the light control device and imaging device of the present disclosure are light control devices or imaging devices that can perform stably for a long period of time.

[0022] <Light Control Device> The light control device of the present disclosure is a light control device including a plurality of liquid crystal light control layers and a retardation layer disposed between the plurality of liquid crystal light control layers, wherein the plurality of liquid crystal light control layers each contain a guest-host liquid crystal composition, and the retardation layer has a softening temperature of 180° C. or higher as measured by thermal analysis. Each layer constituting the light control device of the present disclosure will be described.

[0023] (Liquid Crystal Dimming Layer) The liquid crystal dimming layer of the present disclosure is a layer for controlling optical performance, such as absorbing polarized light in one direction per layer, using voltage, and contains a guest-host liquid crystal composition. The liquid crystal dimming layer of the present disclosure can be a conventionally known liquid crystal dimming layer using a guest-host liquid crystal composition. For example, the liquid crystal dimming layer is formed by encapsulating a guest-host liquid crystal composition in which dichroic dye molecules (guest material) are dissolved in liquid crystal molecules (host material) between two transparent resin polarizing plates coated with transparent conductive layers (transparent electrodes). The dichroic dye (guest) aligns with the host, changing its orientation direction in response to the applied voltage. As a result, the liquid crystal dimming layer containing the guest-host liquid crystal composition continuously changes color intensity depending on the orientation of the dichroic dye. For example, the application of a predetermined voltage can highly align the dichroic dye, increasing light transmittance and making the layer nearly transparent.

[0024] As the guest-host liquid crystal composition, a known guest-host liquid crystal composition conventionally used in a liquid crystal dimming layer can be used. As a combination of a guest material and a host material, any combination of a positive-type or negative-type guest material and a positive-type or negative-type host material can be used. In order to obtain good response characteristics upon voltage application, the host material is preferably a negative type, for example, a vertically aligned nematic guest-host liquid crystal.

[0025] The light control device of the present disclosure includes at least two liquid crystal light control layers. The liquid crystal light control layers of the present disclosure are configured to have a regulated voltage applied thereto, thereby controlling the optical performance of the liquid crystal light control layers. The degree of optical performance of each liquid crystal light control layer may be controlled independently, or the degree of optical performance of multiple liquid crystal light control layers may be controlled collectively.

[0026] (Retardation Layer) —Softening Temperature— The retardation layer of the present disclosure is a layer for changing the phase of light that has passed through at least one liquid crystal dimming layer, and has a softening temperature of 180° C. or higher as determined by thermal analysis. In the present disclosure, the softening temperature is measured by thermal analysis. Thermal analysis is a typical method such as differential scanning calorimetry or thermomechanical analysis, and the softening temperature refers to the lowest temperature among the temperature at which the amount of heat begins to change due to a baseline shift or peak occurrence as determined by differential scanning calorimetry and the temperature at which a softening point is observed as determined by thermomechanical analysis.

[0027] A specific method for measuring the softening temperature is as follows, for example. That is, 20 mg of the retardation layer is sampled, and calorimetry is performed using a differential scanning calorimeter at a heating rate of 10°C / min in a temperature range of 25°C to 725°C. The temperature at which the calorie starts to change due to a baseline shift or a peak, and the lowest temperature at which a softening point is observed when 1 cm2 of the retardation layer is sampled and penetration measurement is performed using a thermomechanical analyzer at a heating rate of 10°C / min, a probe tip diameter of 1 mm, and a temperature range of 25°C to 1500°C, are taken as the softening temperature.

[0028] The retardation layer of the present disclosure has a softening temperature of 180°C or higher as measured as described above. When the softening temperature of the retardation layer is 180°C or higher, for example, fading due to sunlight in a light control device is suppressed, and the light resistance of the light control device is excellent. Preferably, the softening temperature is 250°C or higher. When the softening temperature is 250°C or higher, for example, fading due to sunlight in a light control device is further suppressed, and the light resistance is excellent. Note that fading means that the original color changes, and in the case of a transparent material, it means that the original transparency changes due to coloring, clouding, etc. In the retardation layer of the present disclosure, the upper limit of the softening temperature is 1500°C due to thermal analysis measurements.

[0029] -Retardation Performance- The retardation layer of the present disclosure preferably exhibits a half-wave retardation at a wavelength of 550 nm. That is, it is preferably a λ / 2 plate. The retardation layer of the present disclosure preferably exhibits a half-wave retardation at a wavelength of 440 nm. That is, it is preferably a λ / 2 plate. The retardation layer of the present disclosure preferably is a half-wave plate for light of 550 nm and a half-wave plate for light of 440 nm. The retardation layer of the present disclosure preferably has an Re(550) of 100 nm to 300 nm and an Re(440) of 100 nm to 300 nm.

[0030] In the retardation layer of the present disclosure, it is preferable that the in-plane retardation Re(550) at a wavelength of 550 nm satisfies the relationship of the following formula (A).

[0031] 210nm≦Re(550)≦300nm Formula (A)

[0032] In the retardation layer of the present disclosure, it is more preferable that the in-plane retardation Re(550) at a wavelength of 550 nm satisfies the relationship of the following formula (B).

[0033] 220nm≦Re(550)≦290nm Formula (B)

[0034] To form a retardation layer satisfying the above formula (A) or (B), the amount of irradiation light, heating temperature, film thickness, etc. are appropriately adjusted when forming the retardation layer using a composition for forming the retardation layer. By satisfying the above formula (A) or (B), a retardation layer suitable for the light control device of the present disclosure can be obtained.

[0035] In the retardation layer of the present disclosure, Rth(550), which is the retardation value in the thickness direction at a wavelength of 550 nm, is preferably −150 nm to 150 nm, more preferably −100 nm to 100 nm.

[0036] -Reverse wavelength dispersion- The retardation layer also preferably has reverse wavelength dispersion. Reverse wavelength dispersion refers to a phenomenon in which, when measuring the in-plane retardation (Re) value at a specific wavelength (visible light range), the Re value increases as the measured wavelength increases. It is preferable that Re(450) / Re(550)<1.00 and Re(650) / Re(550)>1.00 are satisfied.

[0037] Furthermore, when forming a retardation layer having reverse wavelength dispersion, it is preferable to use a liquid crystal compound having an absorption maximum in the wavelength range of 300 nm to 400 nm and having a polymerizable group. As long as the above requirements are met, the liquid crystal compound is not particularly limited, and known liquid crystal compounds can be used. The composition containing a liquid crystal compound may contain multiple liquid crystal compounds, as long as at least one of the liquid crystal compounds satisfies the above requirements. Having an absorption maximum in the wavelength range of 300 nm to 400 nm means that a maximum value is found in the wavelength range of 300 nm to 400 nm in the ultraviolet-visible light absorption spectrum in the wavelength range of 200 nm to 800 nm measured with a spectrophotometer using a solution in which the liquid crystal compound is dissolved. When a liquid crystal compound exhibits reverse wavelength dispersion, it often has an absorption maximum in the wavelength range of 300 nm to 400 nm.

[0038] A retardation layer having reverse wavelength dispersion can be produced by uniaxially stretching a polymer film such as a modified polycarbonate resin film having reverse wavelength dispersion, for example, with reference to JP-A-2017-049574, etc. Further, a retardation layer having reverse wavelength dispersion can also be produced by orienting and fixing a rod-shaped liquid crystal compound having reverse wavelength dispersion, for example, with reference to JP-A-2020-084070, etc.

[0039] The retardation layer of the present disclosure preferably contains a liquid crystal compound. The retardation layer preferably contains an optically anisotropic layer (liquid crystal film) formed from a composition containing a liquid crystal compound and including a layer in which the liquid crystal compound is fixed. The liquid crystal compound can align liquid crystal molecules in any direction using an alignment film or the like, thereby simplifying the manufacturing process of the retardation layer. In addition, the thickness of a liquid crystal film can be more easily reduced than that of a polymer film.

[0040] -Optical Anisotropic Layer- The retardation layer preferably includes at least one optically anisotropic layer. The retardation layer may include one optically anisotropic layer or may include multiple optically anisotropic layers. When multiple optically anisotropic layers are included, the multiple optically anisotropic layers are combined to form the retardation layer.

[0041] The retardation performance of the retardation layer is not limited to the above-mentioned retardation performance, and in some cases, a plurality of optically anisotropic layers each having an adjusted retardation performance may be used in combination.

[0042] When the retardation layer includes an optically anisotropic layer, the optically anisotropic layer contains a liquid crystal compound. The case where the optically anisotropic layer is a layer formed by fixing a liquid crystal compound will be described in detail below. The layer formed by fixing a liquid crystal compound is formed from a composition containing at least a liquid crystal compound.

[0043] Liquid Crystal Compounds Liquid crystal compounds are not particularly limited in type, but can be classified into rod-shaped (rod-shaped liquid crystal compounds) and discotic (discotic liquid crystal compounds) liquid crystal compounds based on their shape. Any of these liquid crystal compounds can be used in the present disclosure. Two or more rod-shaped liquid crystal compounds, two or more discotic liquid crystal compounds, or a mixture of a rod-shaped liquid crystal compound and a discotic liquid crystal compound may be used. Preferred rod-shaped liquid crystal compounds include those described in claim 1 of JP-A-11-513019 and paragraphs

[0026] to

[0098] of JP-A-2005-289980. Preferred discotic liquid crystal compounds include, but are not limited to, those described in paragraphs

[0020] to

[0067] of JP-A-2007-108732 and paragraphs

[0013] to

[0108] of JP-A-2010-244038.

[0044] The liquid crystal compound contained in the composition containing a liquid crystal compound preferably has a polymerizable group. Therefore, the retardation layer preferably contains a liquid crystal compound aligned by polymerization. The polymerizable group is preferably a polymerizable group capable of radical polymerization or cation polymerization. As the radical polymerizable group, a commonly known radical polymerizable group can be used, and preferred examples include an acryloyloxy group or a methacryloyloxy group. In this case, it is known that the polymerization rate of an acryloyloxy group is generally fast, and an acryloyloxy group is preferred in terms of improving productivity, but a methacryloyloxy group can also be used as the polymerizable group. As the cation polymerizable group, a commonly known cationic polymerizable group can be used, and specific examples include an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester group, and a vinyloxy group. Among them, an alicyclic ether group or a vinyloxy group is preferred, and an epoxy group, an oxetanyl group, or a vinyloxy group is particularly preferred.

[0045] The liquid crystal compound is preferably a compound having any aromatic ring selected from the group consisting of groups represented by the following formulae (Ar-1) to (Ar-7), in that it exhibits reverse wavelength dispersion.

[0046]

[0047] In the above formulae (Ar-1) to (Ar-7), * represents a bonding position, that is, a bonding position to a portion other than the aromatic ring contained in the liquid crystal compound.

[0048] In the above formula (Ar-1), Q １ represents N or CH, and Q ２ is -S-, -O-, or -N(R ６ )-, R ６ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Y １represents an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent, an aromatic heterocyclic group having 3 to 12 carbon atoms which may have a substituent, or an alicyclic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, and -CH ２ One or more of - may be substituted with -O-, -S- or -NH-.

[0049] Also, Y １ Examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms represented by Y include aryl groups such as a phenyl group, a 2,6-diethylphenyl group, and a naphthyl group. １ Examples of the aromatic heterocyclic group having 3 to 12 carbon atoms represented by Y include heteroaryl groups such as a thienyl group, a thiazolyl group, a furyl group, and a pyridyl group. １ Examples of the alicyclic hydrocarbon group having 6 to 20 carbon atoms represented by Y include a cyclohexylene group, a cyclopentylene group, a norbornylene group, and an adamantylene group. １ Examples of the substituent that may be possessed by include the following substituent X.

[0050] Examples of the substituent X include an alkyl group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, an alkylcarbonyloxy group, an alkylamino group, a dialkylamino group, an alkylamide group, an alkenyl group, an alkynyl group, a halogen atom, a cyano group, a nitro group, an alkylthiol group, and an N-alkylcarbamate group, among which an alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, or a halogen atom is preferred. As the alkyl group, a linear, branched, or cyclic alkyl group having 1 to 18 carbon atoms is preferred, an alkyl group having 1 to 8 carbon atoms is more preferred, an alkyl group having 1 to 4 carbon atoms is even more preferred, and a methyl group or an ethyl group is particularly preferred. As the alkoxy group, an alkoxy group having 1 to 18 carbon atoms is preferred, an alkoxy group having 1 to 8 carbon atoms is more preferred, an alkoxy group having 1 to 4 carbon atoms is even more preferred, and a methoxy group or an ethoxy group is particularly preferred. Examples of the alkoxycarbonyl group include groups in which an oxycarbonyl group (-O-CO- group) is bonded to the alkyl group exemplified above, of which methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, or isopropoxycarbonyl group is preferred, with a methoxycarbonyl group being more preferred. Examples of the alkylcarbonyloxy group include groups in which a carbonyloxy group (-CO-O- group) is bonded to the alkyl group exemplified above, of which methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, or isopropylcarbonyloxy group is preferred, with a methylcarbonyloxy group being more preferred.

[0051] In the above formulas (Ar-1) to (Ar-7), Z １ , Z ２ and Z ３ each independently represents a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a monovalent aromatic heterocyclic group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -OR ７ , -NR ８ R ９ , -SR １０ , -COOR １１, or -COR １２ represents R ７ ~R １２ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Z １ and Z ２ may be bonded to each other to form an aromatic ring.

[0052] Here, the monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group, a tert-pentyl group (1,1-dimethylpropyl group), a tert-butyl group, or a 1,1-dimethyl-3,3-dimethylbutyl group, and particularly preferably a methyl group, an ethyl group, or a tert-butyl group. Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, methylcyclohexyl, and ethylcyclohexyl groups; monocyclic unsaturated hydrocarbon groups such as cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, cyclodecenyl, cyclopentadienyl, cyclohexadienyl, cyclooctadienyl, and cyclodecadiene; bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, and tricyclo[5.2.1.0]diene; ２，６ ]decyl group, tricyclo[3.3.1.1 ３，７ ]decyl group, tetracyclo[6.2.1.1 ３，６ .0 ２，７] polycyclic saturated hydrocarbon groups such as a dodecyl group and an adamantyl group; and the like. Examples of monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms include a phenyl group, a 2,6-diethylphenyl group, a naphthyl group, and a biphenyl group, and aryl groups having 6 to 12 carbon atoms (particularly a phenyl group) are preferred. Examples of monovalent aromatic heterocyclic groups having 6 to 20 carbon atoms include a 4-pyridyl group, a 2-furyl group, a 2-thienyl group, a 2-pyrimidinyl group, and a 2-benzothiazolyl group. Examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and among these, a fluorine atom, a chlorine atom, and a bromine atom are preferred. On the other hand, R ７ ~R １２ Examples of the alkyl group having 1 to 6 carbon atoms represented by include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group.

[0053] In addition, in the above formulas (Ar-2) and (Ar-3), A ３ and A ４ are each independently —O—, —N(R １３ represents a group selected from the group consisting of —, —S—, and —CO—; R １３ represents a hydrogen atom or a substituent. １３ Examples of the substituent represented by include the same as the substituent X described above.

[0054] In the formula (Ar-2), X represents a hydrogen atom or a nonmetallic atom of Groups 14 to 16 which may have a substituent bonded thereto. Examples of the nonmetallic atom of Groups 14 to 16 represented by X include an oxygen atom, a sulfur atom, a hydrogen atom, or a nitrogen atom bonded to a substituent [═N—R Ｎ１ , R Ｎ１ represents a hydrogen atom or a substituent.], and a carbon atom to which a hydrogen atom or a substituent is bonded [═C—(R Ｃ１ ) ２ , R Ｃ１represents a hydrogen atom or a substituent. Examples of the substituent include an alkyl group, an alkoxy group, an alkyl-substituted alkoxy group, a cyclic alkyl group, an aryl group (e.g., a phenyl group, a naphthyl group, etc.), a cyano group, an amino group, a nitro group, an alkylcarbonyl group, a sulfo group, and a hydroxyl group.

[0055] In addition, in the above formula (Ar-3), D ７ and D ８ each independently represents a single bond, or —CO—, —O—, —S—, —C(═S)—, or —CR １ R ２ -, -CR ３ =CR ４ -, -NR ５ -, or a divalent linking group formed by a combination of two or more thereof, R １ ~R ５ each independently represents a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 12 carbon atoms.

[0056] Here, D ７ and D ８ Examples of the divalent linking group in one embodiment include -CO-, -O-, -CO-O-, -C(=S)O-, and -CR １ R ２ -, -CR １ R ２ -CR １ R ２ -, -O-CR １ R ２ -, -CR １ R ２ -O-CR １ R ２ -, -CO-O-CR １ R ２ -, -O-CO-CR １ R ２ -, -CR １ R ２ -O-CO-CR １ R ２ -, -CR １ R ２ -CO-O-CR １ R ２ -, -NR ５ -CR １ R ２- and -CO-NR ５ - etc. １ , R ２ and R ５ each independently represents a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 12 carbon atoms. Among these, —CO—, —O—, and —CO—O— are preferred.

[0057] In the above formula (Ar-3), SP ３ and SP ４ are each independently a single bond, a linear or branched alkylene group having 1 to 12 carbon atoms, or a —CH ２ represents a divalent linking group in which one or more -'s are substituted with -O-, -S-, -NH-, -N(Q)-, or -CO-, and Q represents a substituent. Examples of the substituent include the same as those for the substituent X described above.

[0058] Here, SP ３ and SP ４ Suitable examples of the linear or branched alkylene group having 1 to 12 carbon atoms shown in one embodiment of (1) above include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a methylhexylene group, and a heptylene group.

[0059] In the above formula (Ar-3), L ３ and L ４Each independently represents a monovalent organic group. Examples of monovalent organic groups include an alkyl group, an aryl group, and a heteroaryl group. The alkyl group may be linear, branched, or cyclic, but is preferably linear. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20, and even more preferably 1 to 10. The aryl group may be monocyclic or polycyclic, but is preferably monocyclic. The aryl group preferably has 6 to 25 carbon atoms, more preferably 6 to 10. The heteroaryl group may be monocyclic or polycyclic. The number of heteroatoms constituting the heteroaryl group is preferably 1 to 3. The heteroatoms constituting the heteroaryl group are preferably nitrogen atoms, sulfur atoms, or oxygen atoms. The heteroaryl group preferably has 6 to 18 carbon atoms, more preferably 6 to 12. The alkyl group, aryl group, and heteroaryl group may be unsubstituted or may have a substituent. Examples of the substituent include the same as those described above for the substituent X.

[0060] In the above formulas (Ar-4) to (Ar-7), Ax represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles. In addition, in the above formulas (Ar-4) to (Ar-7), Ay represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles. Here, the aromatic rings in Ax and Ay may have a substituent, and Ax and Ay may be bonded to form a ring. In addition, Q ３ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms which may have a substituent. Examples of Ax and Ay include those described in paragraphs

[0039] to

[0095] of WO 2014 / 010325. ３Examples of the alkyl group having 1 to 20 carbon atoms represented by include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group, and examples of the substituent include those similar to the substituent X described above.

[0061] The liquid crystal compound used in the present disclosure is preferably a compound represented by the following formula (I), because it has high refractive index anisotropy and therefore allows the optically anisotropic layer to be made thinner. In the following formula (I), Ar represents any aromatic ring selected from the group consisting of groups represented by the above formulas (Ar-1) to (Ar-7). However, when q1 in the following formula (I) is 2, the multiple Ars may be the same or different.

[0062] L １ -SP １１ -D ５ - (A １ ) ａ１ -D ３ - (G １ ) ｇ１ -D １ -[Ar-D ２ 〕 ｑ１ - (G ２ ) ｇ２ -D ４ - (A ２ ) ａ２ -D ６ -SP 12 -L ２ ...(I)

[0063] In the above formula (I), a1, a2, g1, and g2 each independently represent 0 or 1. However, at least one of a1 and g1 represents 1, and at least one of a2 and g2 represents 1. In addition, in the above formula (I), q1 represents 1 or 2. In addition, in the above formula (I), D １ , D ２ , D ３ , D ４ , D ５ and D ６ each independently represents a single bond, or —CO—, —O—, —S—, —C(═S)—, or —CR １１ R １２-, -CR １３ =CR １４ -, -NR １５ -, or a divalent linking group formed by a combination of two or more thereof, R １１ ~R １５ each independently represents a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 12 carbon atoms. However, when q1 is 2, a plurality of D ２ may be the same or different. １ and G ２ each independently represents an aromatic ring having 6 to 20 carbon atoms which may have a substituent, or a divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms which may have a substituent, and -CH ２ In the above formula (I), one or more of A may be substituted with -O-, -S- or -NH-. １ and A ２ each independently represents an aromatic ring having 6 to 20 carbon atoms which may have a substituent, or a divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms which may have a substituent, and -CH ２ In the above formula (I), one or more of - may be substituted with -O-, -S- or -NH-. １１ and SP １２ are each independently a single bond, a linear or branched alkylene group having 1 to 12 carbon atoms, or a —CH ２ represents a divalent linking group in which one or more of - is substituted with -O-, -S-, -NH-, -N(Q)-, or -CO-, and Q represents a substituent. １ and L ２ each independently represents a monovalent organic group; １ and L ２ At least one of the groups represented by the formula (Ar-3) represents a polymerizable group. １ and L ２ and L in the above formula (Ar-3). ３ and L ４At least one of the groups represents a polymerizable group.

[0064] In the formula (I), a1, a2, g1, and g2 are all preferably 1. In addition, in the formula (I), q1 is preferably 1.

[0065] In the above formula (I), D １ , D ２ , D ３ , D ４ , D ５ and D ６ The divalent linking group shown in one embodiment of the formula (Ar-3) is D ７ and D ８ Among these, any one of —CO—, —O—, and —CO—O— is preferable.

[0066] In the above formula (I), G １ and G ２ Examples of the aromatic ring having 6 to 20 carbon atoms in one embodiment of the formula (1) include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthroline ring; and aromatic heterocycles such as a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, and a benzothiazole ring; and among these, a benzene ring (for example, a 1,4-phenyl group) is preferred.

[0067] In the above formula (I), G １ and G ２ The divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms shown in one embodiment of (1) is preferably a 5-membered or 6-membered ring. The alicyclic hydrocarbon group may be saturated or unsaturated, but is preferably a saturated alicyclic hydrocarbon group. １ and G ２ For the divalent alicyclic hydrocarbon group represented by the formula (I), reference can be made to, for example, paragraph

[0078] of JP-A-2012-21068, the contents of which are incorporated herein by reference.

[0068] G in the above formula (I) １ and G ２is preferably a cycloalkane ring. Examples of the cycloalkane ring include a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclododecane ring, and a cyclodocosane ring. Of these, a cyclohexane ring is preferred, a 1,4-cyclohexylene group is more preferred, and a trans-1,4-cyclohexylene group is even more preferred.

[0069] In addition, in the above formula (I), G １ and G ２ With regard to the above, examples of the substituent that the aromatic ring having 6 to 20 carbon atoms or the divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms may have include Y １ Examples of the substituents include the same as those that may be possessed by the group.

[0070] In the above formula (I), A １ and A ２ As an aromatic ring having 6 to 20 carbon atoms in one embodiment, G in the above formula (I) １ and G ２ In addition, in the above formula (I), A １ and A ２ As an embodiment of the divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms, there is mentioned G １ and G ２ The same as those explained in A １ and A ２ With regard to the above, examples of the substituent that the aromatic ring having 6 to 20 carbon atoms or the divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms may have include the same as the substituent X described above.

[0071] In the above formula (I), SP １１ and SP １２ The linear or branched alkylene group having 1 to 12 carbon atoms in one embodiment of the formula (Ar-3) is, for example, SP ３ and SP ４ Examples of the above-described examples are the same as those described above.

[0072] In the above formula (I), L １ and L ２The monovalent organic group represented by the formula (Ar-3) is ３ and L ４ Examples of the above-described examples are the same as those described above.

[0073] In the above formula (I), L １ and L ２ The polymerizable group represented by at least one of the above groups includes the above-mentioned radically polymerizable or cationic polymerizable groups.

[0074] In the above formula (I), L in the above formula (I) is preferably 0.01 to 0.15 because it improves durability. １ and L ２ However, each of them is preferably a polymerizable group, and more preferably an acryloyloxy group or a methacryloyloxy group.

[0075] Examples of the compound represented by formula (I) include compounds represented by general formula (1) described in JP-A-2010-084032 (particularly, compounds described in paragraphs

[0067] to

[0073] ), compounds represented by general formula (II) described in JP-A-2016-053709 (particularly, compounds described in paragraphs

[0036] to

[0043] ), and compounds represented by general formula (1) described in JP-A-2016-081035 (particularly, compounds described in paragraphs

[0043] to

[0055] ).

[0076] For example, specific examples of the rod-shaped liquid crystal compound include a polymerizable liquid crystal composition LA-1 represented by the following formula (1), a polymerizable liquid crystal composition LA-2 represented by the following formula (2), a polymerizable liquid crystal composition LA-3 represented by the following formula (3), a polymerizable liquid crystal composition LA-4 represented by the following formula (4), and a polymerizable liquid crystal composition LA-5 represented by the following formula (5).

[0077]

[0078] In formula (1), tBu represents a tertiary butyl group.

[0079]

[0080]

[0081]

[0082]

[0083] In formula (5), Me represents a methyl group.

[0084] Specific examples of the discotic liquid crystal compound include a discotic liquid crystal compound (A) represented by the following formula (6) and a discotic liquid crystal compound (B) represented by the following formula (7).

[0085]

[0086]

[0087] The liquid crystal compound composition may be, for example, a conventionally known compound used in a composition for forming a coating film, and may contain components other than the liquid crystal compound described above. For example, the composition may contain a polymerization initiator. The polymerization initiator used is selected depending on the type of polymerization reaction, and examples include thermal polymerization initiators and photopolymerization initiators. Examples of photopolymerization initiators include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, and combinations of triarylimidazole dimers and p-aminophenyl ketones. The amount of polymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the total solids content of the composition.

[0088] The composition may also contain a polymerizable monomer from the viewpoint of the uniformity and strength of the coating film. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Polyfunctional radically polymerizable monomers are preferred, and those copolymerizable with the above-mentioned polymerizable group-containing liquid crystal compound are preferred. Examples include those described in paragraphs

[0018] to

[0020] of JP-A No. 2002-296423. The amount of the polymerizable monomer added is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, based on the total mass of the liquid crystal compound.

[0089] The composition may also contain a surfactant from the viewpoint of the uniformity and strength of the coating film. Examples of surfactants include conventionally known compounds. Examples include silicone surfactants, fluorine surfactants, and acrylic surfactants.

[0090] The composition may also contain a solvent, and organic solvents are preferably used. Examples of organic solvents include amides (e.g., N,N-dimethylformamide), sulfoxides (e.g., dimethyl sulfoxide), heterocyclic compounds (e.g., pyridine), hydrocarbons (e.g., benzene, hexane), alkyl halides (e.g., chloroform, dichloromethane), esters (e.g., methyl acetate, ethyl acetate, butyl acetate), ketones (e.g., acetone, methyl ethyl ketone), and ethers (e.g., tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.

[0091] The composition may also contain various alignment agents, such as a vertical alignment promoter, such as a polarizer interface side vertical alignment agent or an air interface side vertical alignment agent, and a horizontal alignment promoter, such as a polarizer interface side horizontal alignment agent or an air interface side horizontal alignment agent.

[0092] Furthermore, the composition may contain, in addition to the above components, an adhesion improver, a plasticizer, a polymer, and the like.

[0093] The method for forming the optically anisotropic layer is not particularly limited, and known methods can be used. For example, a composition for forming an optically anisotropic layer containing a liquid crystal compound is applied to a predetermined support (including a temporary substrate) to form a coating film, and the resulting coating film is subjected to a curing treatment (irradiation with ultraviolet rays (light irradiation treatment) or heat treatment), thereby producing an optically anisotropic layer in which the liquid crystal compound is fixed. Note that an alignment layer, which will be described later, may also be used if necessary.

[0094] The composition can be applied by a known method (for example, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, or die coating).

[0095] Next, the formed coating film is subjected to an alignment treatment to align the liquid crystal compound in the coating film. The alignment treatment can be performed by drying the coating film at room temperature or by heating the coating film. The conditions for heating the coating film are not particularly limited, but the heating temperature is preferably 50 to 250°C, more preferably 50 to 150°C, and the heating time is preferably 10 seconds to 10 minutes. After heating the coating film, the coating film may be cooled, if necessary, before the curing treatment (light irradiation treatment) described below. The cooling temperature is preferably 20 to 200°C, more preferably 30 to 150°C.

[0096] Next, the coating film in which the liquid crystal compound has been aligned is subjected to a curing treatment. The method of curing the coating film in which the liquid crystal compound has been aligned is not particularly limited, and examples thereof include light irradiation treatment and heat treatment. Among these, from the viewpoint of manufacturability, light irradiation treatment is preferred, and ultraviolet irradiation treatment is more preferred. The irradiation conditions for the light irradiation treatment are not particularly limited, but are preferably 50 to 1000 mJ / cm. ２ The atmosphere during the light irradiation treatment is not particularly limited, but a nitrogen atmosphere is preferred.

[0097] (Support) Any support can be used as long as it is self-supporting. In order to form a uniform optically anisotropic layer over a wide area, a film, sheet, or flat support is preferred. For industrial continuous production, a long film or sheet can also be used. Examples of such supports include glass substrates and polymer films, and examples of materials for polymer films include cellulose-based polymers; acrylic polymers having acrylic ester polymers such as polymethyl methacrylate and lactone ring-containing polymers; thermoplastic norbornene-based polymers; polycarbonate-based polymers; polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate; styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers (AS resins); polyolefin-based polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers; vinyl chloride-based polymers; amide-based polymers such as nylon and aromatic polyamides; imide-based polymers; sulfone-based polymers; polyethersulfone-based polymers; polyetheretherketone-based polymers; polyphenylene sulfide-based polymers; vinylidene chloride-based polymers; vinyl alcohol-based polymers; vinyl butyral-based polymers; arylate-based polymers; polyoxymethylene-based polymers; epoxy-based polymers; or polymers containing mixtures of these polymers.

[0098] The thickness of the support is not particularly limited, but it is preferable that the support has sufficient self-supporting properties and strength to withstand the process of forming the optically anisotropic layer. For example, it is preferably 5 to 200 μm, more preferably 10 to 100 μm, and even more preferably 20 to 90 μm. Furthermore, the support may be one that can be peeled off and removed as needed after the optically anisotropic layer is formed.

[0099] Due to the need to efficiently control the liquid crystal molecules in a composition to a desired alignment state, it is common to impart an alignment restraining force to the surface of a support. Known methods for imparting an alignment restraining force include providing an alignment film and optionally further treating the film, and directly treating the support surface. Examples of methods for providing an alignment film and optionally further treating the film include coating a thin resin layer on the film and then rubbing the surface (rubbing method), and coating a material that exhibits an alignment restraining force in a specific direction upon polarized light irradiation and then irradiating the film with polarized light in the desired direction (photoalignment method). In particular, photoalignment has become popular in recent years because it allows for imparting an alignment restraining force in any direction simply by controlling the polarization axis of the irradiated linearly polarized light. Materials for alignment films (photo-alignment films) that can be used in such photo-alignment methods include polymer materials such as photo-alignment polymers, polyamide compounds, and polyimide compounds having a cinnamoyl structure; liquid crystal alignment films formed by liquid crystal alignment agents having photo-alignment groups described in JP 2012-155308 A; and LPP-JP265CP, a product name manufactured by Rolic Technologies, Inc.

[0100] The thickness of the alignment film is not particularly limited, but is, for example, preferably 0.01 to 10 μm, more preferably 0.01 to 1 μm, and even more preferably 0.01 to 0.5 μm. Furthermore, the alignment film may be one that can be peeled off and removed as needed after the optically anisotropic layer is formed.

[0101] (Configuration of light control device) The light control device of the present disclosure includes a plurality of liquid crystal light control layers and a retardation layer disposed between the plurality of liquid crystal light control layers. The plurality of liquid crystal light control layers and the retardation layer can be appropriately combined depending on the purpose of light control, etc., as long as the retardation layer is disposed between the plurality of liquid crystal light control layers. In this way, by using a liquid crystal light control layer and a retardation layer in combination, it is possible to improve the symmetry of the incident angle characteristics while maintaining the light control performance, compared to when no retardation layer is used.

[0102] As a specific example of the configuration of the light control device, when the retardation layer is composed of only a single optically anisotropic layer, the single optically anisotropic layer is preferably a λ / 2 plate (half-wave plate). When the single optically anisotropic layer contains a rod-shaped liquid crystal compound, the liquid crystal compound is preferably horizontally aligned. Furthermore, when the single optically anisotropic layer is formed from a composition containing a discotic liquid crystal compound, the liquid crystal compound is preferably vertically aligned.

[0103] In this case, the light control device preferably includes a fixation layer that fixes the liquid crystal light control layer and the retardation layer, and has a first liquid crystal light control layer, a fixation layer, a retardation layer, a fixation layer, and a second liquid crystal light control layer in this order. For example, as shown in FIG. 1, a first liquid crystal light control layer 11 and a second liquid crystal light control layer 14, and a retardation layer 13 (a single-layer optically anisotropic layer) prepared in the same manner are used as the liquid crystal light control layer, and a light control device 10 having a configuration in this order of the first liquid crystal light control layer 11, a fixation layer 12, a retardation layer 13, a fixation layer 12, and a second liquid crystal light control layer 14 is preferably mentioned. In this case, the retardation layer 13 is a half-wave plate. The light control device 10 configured as described above can more reliably reduce light.

[0104] The immobilization layer 12 may be made of a conventional material, preferably a pressure-sensitive adhesive or adhesive. As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive is preferably used. As the adhesive, a water-based adhesive such as polyvinyl alcohol, or an acrylic or epoxy curing adhesive is preferably used.

[0105] When the retardation layer is formed from multiple layers, i.e., when it includes at least a first optically anisotropic layer and a second optically anisotropic layer, the first optically anisotropic layer and the second optically anisotropic layer are preferably optically anisotropic layers each exhibiting an in-plane retardation of 120 nm to 160 nm at a wavelength of 550 nm. The first optically anisotropic layer and the second optically anisotropic layer are preferably λ / 4 plates (also referred to as plates having λ / 4 function or plates having a 1 / 4 wavelength retarder). A λ / 2 plate serving as a retardation layer can be obtained by laminating or directly coating and laminating λ / 4 plates serving as optically anisotropic layers. Here, "having λ / 4 function" refers to the function of converting linearly polarized light of a certain wavelength into circularly polarized light (or circularly polarized light into linearly polarized light). The angle between the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is preferably 0°±10°. It is preferable that the retardation layer as a whole satisfies the above formula (1).

[0106] Specific examples of the configuration of the light control device include, for example, a light control device 20 having a configuration in which a first liquid crystal light control layer 11 and a second liquid crystal light control layer 14, which are similarly prepared, are used as the liquid crystal light control layers, and a first optically anisotropic layer 15 and a second optically anisotropic layer 16, which are similarly prepared, are used as the retardation layer, and the first liquid crystal light control layer 11, the fixation layer 12, the first optically anisotropic layer 15, the fixation layer 12, the second optically anisotropic layer 16, the fixation layer 12, and the second liquid crystal light control layer 14 are arranged in this order, as shown in FIG. In this case, the first optically anisotropic layer 15 and the second optically anisotropic layer 16 are each a quarter-wave plate. The entire combination of the first optically anisotropic layer 15, the fixation layer 12, and the second optically anisotropic layer 16 can be used as a retardation layer. The light control device 20 having the above configuration can more reliably reduce light.

[0107] The light control device may have layers that impart various functions in addition to the liquid crystal light control layer, retardation layer, etc. Examples include an ultraviolet-cutting film that cuts ultraviolet rays and an anti-reflection layer that suppresses reflection.

[0108] <Imaging device> The imaging device of the present disclosure includes the light control device of the present disclosure. When the light control device of the present disclosure is included in the imaging device, it has excellent light resistance and suppresses fading even when light is focused by a lens. Therefore, the light control device of the present disclosure can be included in various imaging devices and can exhibit excellent light resistance in any imaging device.

[0109] The light control device of the present disclosure has excellent light resistance, and therefore, by incorporating it into an imaging device, it can be used while maintaining its light control performance for a long period of time. Note that, in addition to being incorporated into an imaging device, the light control device of the present disclosure can be placed anywhere on the incident light side of the lens or the imaging sensor, as long as it is on the incident light side.

[0110] In an imaging device, the light control device may be configured to be removable from the optical path. Since a light control device using a guest-host liquid crystal contains a dye in advance, inserting it into the optical path inevitably sacrifices maximum transmittance. Therefore, a mechanism for retracting the device from the optical path as needed may be provided.

[0111] A specific example of the imaging device of the present disclosure is a digital camera. As shown in Fig. 3, in a digital camera 30, a lens 31, a light control device 10, and an imaging sensor 33 are preferably arranged in this order from the incident side. The light control device 10 and the imaging sensor 33 are arranged inside a housing 32. With this configuration, the light control device 10 can provide the digital camera 30 with appropriate light control performance for a long period of time.

[0112] As described above, the light control device and the imaging device of the present disclosure have liquid crystal light control layers each containing a guest-host liquid crystal composition, and a retardation layer having a softening temperature of 180°C or higher as measured by thermal analysis. Therefore, the light control device and the imaging device have excellent light resistance and are suppressed from fading even when light is focused by a lens, for example.

[0113] The present disclosure will be described in more detail below based on examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present disclosure. Therefore, the scope of the present disclosure should not be interpreted as being limited by the examples shown below.

[0114] Example 1 (Preparation of Cellulose Ester Film A1) The following composition (cellulose ester solution A-1) was charged into a mixing tank, stirred, and heated at 90°C for 10 minutes. After heating, the resulting composition was filtered through filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope. The solid content of the dope was 23.5% by mass based on the total mass of the dope, and the solvent for the dope was methylene chloride / methanol / butanol = 81 / 18 / 1 (mass ratio, based on the total mass of the solvent). In the following composition, sugar ester compound 1 and sugar ester compound 2 are plasticizers.

[0115] Cellulose ester solution A-1: ​​cellulose acylate (acetyl substitution degree 2.86, viscosity average polymerization degree 310) 100 parts by mass sugar ester compound 1 (formula (8) below) 6.0 parts by mass sugar ester compound 2 (formula (9) below) 2.0 parts by mass silica particle dispersion (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 0.1 parts by mass solvent (methylene chloride / methanol / butanol) 351.9 parts by mass

[0116]

[0117] In formula (8), R is a benzoyl group or a hydrogen atom, and the average degree of substitution is 5.7.

[0118]

[0119] In formula (9), R is an acetyl group or an isobutyryl group, and the ratio of acetyl groups to isobutyryl groups (acetyl groups / isobutyryl groups) is 2 / 6.

[0120] The dope prepared above was cast using a drum film-forming machine. The dope was cast from a die onto a metal support cooled to 0°C so that it was in contact with the support. After casting, the resulting web (film) was peeled off from the drum. The drum was made of SUS (stainless steel). The cast web was peeled off from the drum and dried for 20 minutes in a tenter apparatus, which clipped both ends of the web with clips while transporting the film at 30°C to 40°C. The web was then post-dried by zone heating while being transported by a roll. The resulting web was knurled and then wound up. The wound film was used as cellulose acylate film A1. The resulting cellulose acylate film A1 (TAC film) had a thickness of 60 μm, an in-plane retardation Re(550) of 1 nm at a wavelength of 550 nm, and a thickness-direction retardation Rth(550) of 35 nm at a wavelength of 550 nm.

[0121] (Preparation of Retardation Layer 1) A coating solution E-1 for forming a photo-alignment film having the following composition was continuously applied onto the above-mentioned cellulose acylate film A1 using a wire bar. The cellulose acylate film A1 on which the coating film was formed was dried with hot air at 140°C for 120 seconds, and then irradiated with alternating ultraviolet light (10 mJ / cm ２ , using an ultra-high pressure mercury lamp) to form a photo-alignment film E1 with a thickness of 0.2 μm, thereby obtaining a TAC film with a photo-alignment film.

[0122] Coating liquid E-1 for forming a photo-alignment film: Polymer represented by the following formula (10): (In the following formula (10), the numerical value described for each repeating unit represents the content (mass%) of each repeating unit relative to all repeating units. Weight average molecular weight: 45,000) 100.00 parts by mass Acid generator (CPI-110TF, manufactured by San-Apro Co., Ltd., the following formula (11)) 0.005 parts by mass Isopropyl alcohol 16.50 parts by mass Butyl acetate 1,072.00 parts by mass Methyl ethyl ketone 268.00 parts by mass

[0123]

[0124]

[0125] Composition F-1 (composition F-1 for forming a retardation layer) having the following composition was applied onto the photo-alignment film E1 using a bar coater (#14.0). The coating film formed on the photo-alignment film E1 was heated to 120°C with hot air, cooled to 60°C after heating, and then irradiated with 100 mJ / cm at a wavelength of 365 nm using high-pressure mercury or the like under a nitrogen atmosphere. ２ The coating film was irradiated with ultraviolet light of 500 mJ / cm 2 while being heated to 120°C. ２ The coating film was irradiated with ultraviolet light of 1000 nm to fix the alignment of the liquid crystal compound, thereby producing a retardation layer 1. As shown in Fig. 4, an optical laminate 1 (40) was obtained in which a cellulose acylate film A1 (41) / a photo-alignment film E1 (42) / a retardation layer 1 (13) were laminated in this order.

[0126] The thickness of the retardation layer 1 was 4.8 μm, and it was a half-wave retarder at 550 nm, with Re(550)=275 nm, and also a half-wave retarder at 440 nm, with Re(440)=220 nm.

[0127] Retardation layer forming composition F-1: Polymerizable liquid crystal composition LA-1 (the above formula (1)) 45.40 parts by mass Polymerizable liquid crystal composition LA-2 (the above formula (2)) 21.80 parts by mass Polymerizable liquid crystal composition LA-3 (the above formula (3)) 20.00 parts by mass Polymerizable liquid crystal composition LA-4 (the above formula (4)) 7.80 parts by mass Polymerizable liquid crystal composition LA-5 (the above formula (5)) 5.00 parts by mass Polymerization initiator PI-1 (the following formula (12)) 0.50 parts by mass Surfactant KA-1 (the following formula (13)) 0.50 parts by mass Cyclopentanone 258.18 parts by mass Methyl ethyl ketone 77.12 parts by mass

[0128]

[0129]

[0130] In formula (13), the numerical value shown for each repeating unit represents the repeat content (% by mass) of the repeating unit relative to all repeating units. The weight average molecular weight (Mw) of formula (13) is 20,000.

[0131] (Fabrication of light control device 1) With reference to Japanese Patent No. 6549335, the surface of the retardation layer 1 of the optical laminate 1 was bonded to the host-guest liquid crystal layer 1 using an acrylic adhesive (manufactured by Nitto Denko Corporation) as a fixation layer. The cellulose acylate film A1 / photo-alignment film E1 were peeled off from the bonded optical laminate 1, and the retardation layer 1 was laminated. A host-guest liquid crystal layer 2 prepared in the same manner as the host-guest liquid crystal layer 1 was further laminated on the retardation layer 1 using the acrylic adhesive, thereby fabricating a light control device 1 in which the host-guest liquid crystal layer 1 / fixation layer (adhesive) / retardation layer 1 / fixation layer (adhesive) / host-guest liquid crystal layer 2 were laminated in this order (see FIG. 1 ).

[0132] (Example 2) (Preparation of Optically Anisotropic Layer 1) The composition F-1 was applied onto the photo-alignment film E1 using a bar coater (#7.0). The coating film formed on the photo-alignment film E1 was heated to 120°C with hot air, cooled to 60°C after heating, and then irradiated with 100 mJ / cm at a wavelength of 365 nm using high-pressure mercury or the like in a nitrogen atmosphere. ２ The coating film was irradiated with ultraviolet light of 500 mJ / cm 2 while being heated to 120°C. ２ The coating film was irradiated with ultraviolet light of 1000 nm to fix the alignment of the liquid crystal compound, thereby producing an optically anisotropic layer 1, and an optical laminate 2 was obtained in which a cellulose acylate film A1 / a photo-alignment film E1 / an optically anisotropic layer 1 were laminated in this order (see Figure 4).

[0133] The optically anisotropic layer 1 had a thickness of 2.5 μm and was a quarter wave retarder at 550 nm with Re(550)=144 nm, and also a quarter wave retarder at 440 nm with Re(440)=118 nm.

[0134] (Preparation of Retardation Layer 2 and Light Control Device 2) Using the same host-guest liquid crystal layer 1 as in Example 1, the cellulose acylate film A1 / photo-alignment film E1 was peeled off from the optical laminate 2 to obtain a laminate in which the host-guest liquid crystal layer 1 / fixation layer (adhesive) / optically anisotropic layer 1 were laminated in this order. Furthermore, a new optically anisotropic layer 1 was laminated on the optically anisotropic layer 1 of the laminate using the above-mentioned acrylic adhesive, and a host-guest liquid crystal layer 2 prepared in the same manner as the host-guest liquid crystal layer 1 was further laminated using the above-mentioned acrylic adhesive, thereby producing a light control device 2. The light control device 2 was laminated in the following order: host-guest liquid crystal layer 1 / fixation layer (adhesive) / optically anisotropic layer 1 / fixation layer (adhesive) / optically anisotropic layer 1 / fixation layer (adhesive) / host-guest liquid crystal layer 2 (see FIG. 2). The two optically anisotropic layers 1 were bonded together so that the angle between the slow axes was 0°. In the configuration of the light control device 2, a laminate having a configuration of optically anisotropic layer 1 / fixing layer (adhesive) / optically anisotropic layer 1 was used as the retardation layer 2.

[0135] (Example 3) (Preparation of Cellulose Ester Solution A-2) The following composition (Cellulose Ester Solution A-2) was charged into a mixing tank, and the composition was stirred while being heated to dissolve each component, thereby preparing Cellulose Ester Solution A-2.

[0136] Cellulose ester solution A-2: Cellulose acylate (acetyl substitution degree 2.86) 100 parts by mass, methylene chloride (first solvent) 320 parts by mass, methanol (second solvent) 83 parts by mass, 1-butanol (second solvent) 3 parts by mass, triphenyl phosphate 7.6 parts by mass, biphenyl diphenyl phosphate 3.8 parts by mass

[0137] (Preparation of Matting Agent Dispersion B-1) The following composition was placed in a disperser and stirred to dissolve each component, thereby preparing Matting Agent Dispersion B-1.

[0138] Matting agent dispersion B-1: AEROSIL R972 (manufactured by Nippon Aerosil Co., Ltd.) 10.0 parts by mass Methylene chloride 72.8 parts by mass Methanol 3.9 parts by mass Butanol 0.5 parts by mass Cellulose ester solution A-2 10.3 parts by mass

[0139] (Preparation of UV absorber solution C-1) The following composition was charged into another mixing tank, and the composition was stirred while being heated to dissolve each component, thereby preparing UV absorber solution C-1.

[0140] Ultraviolet absorber solution C-1: Ultraviolet absorber UV-1 (the following formula (14)) 10.0 parts by mass Ultraviolet absorber UV-2 (the following formula (15)) 10.0 parts by mass Methylene chloride 55.7 parts by mass Methanol 10.0 parts by mass Butanol 1.3 parts by mass Cellulose ester solution A-2 12.9 parts by mass

[0141]

[0142]

[0143] In formulas (14) and (15), -tert indicates tertiary.

[0144] (Preparation of Cellulose Ester Film A2) 94.6 parts by mass of Cellulose Ester Solution A-2 and 1.3 parts by mass of Matting Agent Dispersion B-1 were mixed together to obtain a mixture, to which UV absorber solution C-1 was added so that the UV absorber (UV-1, formula (14)) and UV absorber (UV-2, formula (15)) were each 1.0 part by mass per 100 parts by mass of cellulose acylate. After the addition of the UV absorber solution, the mixture was thoroughly stirred while heated to dissolve each component, thereby preparing a dope. The obtained dope was heated to 30°C and passed through a casting giesser. The heated dope was cast onto a mirror-finished stainless steel support drum with a diameter of 3 m. The surface temperature of the mirror-finished stainless steel support was set to -5°C, and the coating width was 1,470 mm. The film (dope film) formed by casting the dope was blown onto the drum with 34°C dry air for 150 m. ３The film was dried by exposing it to a drying machine at 1000 kJ / min, and when the residual solvent in the film reached 150%, the film was peeled off from the drum. During peeling, the film was stretched by 15% along the film transport direction (longitudinal direction). Thereafter, the film was transported while being held at both ends in the width direction (direction perpendicular to the casting direction) with pin tenters (the pin tenter shown in FIG. 3 of JP-A-4-1009), and no stretching treatment was performed in the width direction. The obtained film was further dried by transporting it between the rolls of a heat treatment device to produce cellulose acylate film A-2.

[0145] The resulting continuous cellulose acylate film A-2 had a residual solvent content of 0.2%, a thickness of 40 μm, and Re and Rth at 550 nm of 0.8 nm and 40 nm, respectively.

[0146] (Alkaline Saponification Treatment) The cellulose acylate film A-2 was passed through a dielectric heating roll at a temperature of 60° C., and the surface temperature of the cellulose acylate film was raised to 40° C. After the temperature was raised, an alkaline solution having the composition shown below was applied to the band surface (the surface that had been in contact with the drum) of the cellulose acylate film using a bar coater in an amount of 14 ml / m. ２ Next, the cellulose acylate film A-2 coated with the alkaline solution was transported for 10 seconds under a steam-type far-infrared heater (manufactured by Noritake Co., Ltd.) heated to 110°C. Subsequently, using a bar coater in the same manner as above, pure water was applied to the obtained cellulose acylate film A-2 at a concentration of 3 ml / m. ２ The resulting cellulose acylate film A-2 was then washed with water using a fountain coater and then drained with an air knife, which was repeated three times. After draining, the resulting cellulose acylate film A-2 was transported to a drying zone at 70°C for 10 seconds and dried, thereby preparing an alkali-saponified cellulose acylate film A-2.

[0147] Alkaline solution: Potassium hydroxide 4.7 parts by mass Water 15.8 parts by mass Isopropanol 63.7 parts by mass Surfactant SF-1, ([C １４ H２９ O-(CH ２ CH ２ O) ２ ]OH) 1.0 part by mass Propylene glycol 14.8 parts by mass

[0148] (Formation of Orientation Film E2) On the surface of the cellulose acylate film A-2 that had been subjected to alkaline saponification treatment, an orientation film coating solution E-2 having the following composition was continuously coated using a wire bar #14. After coating, the cellulose acylate film A-2 coated with the orientation film coating solution was dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds to form an orientation film E2.

[0149] Alignment film coating solution E-2: Modified polyvinyl alcohol (formula (16) below) 10 parts by mass Water 308 parts by mass Methanol 70 parts by mass Isopropanol 29 parts by mass Photopolymerization initiator (Irgacure 2959, manufactured by Ciba Japan KK) 0.8 parts by mass

[0150]

[0151] In formula (16), the numerical value for each repeating unit represents the content (mass%) of each repeating unit relative to all repeating units. Weight average molecular weight: 20,000

[0152] (Formation of Retardation Layer 3) The alignment film prepared above was continuously subjected to rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveying direction, and the angle between the longitudinal direction of the film (conveying direction) and the rotation axis of the rubbing roller was 45 degrees.

[0153] A retardation layer-forming composition F-3 containing a discotic liquid crystal (DLC) compound of the following composition was continuously applied to the alignment film that had been subjected to the above-mentioned rubbing treatment using a #6.0 wire bar. The film conveying speed (V) was set to 26 m / min. In order to dry the solvent in the coating solution and to ripen the alignment of the discotic liquid crystal compound, the film coated with the retardation layer-forming composition F-3 was heated with hot air at 115°C for 90 seconds, and then with hot air at 80°C for 60 seconds. After heating, the obtained film was irradiated with UV (ultraviolet light) at 80°C (exposure amount: 70 mJ / cm ２) was carried out to fix the alignment of the liquid crystal compound, and a retardation layer 3 was formed, thereby obtaining an optical laminate 3 (structure: cellulose acylate film A-2 / alignment film E2 / retardation layer 3) (see FIG. 4).

[0154] The thickness of the retardation layer 3 was 2.4 μm. The average tilt angle of the disc surface of the DLC compound relative to the film surface was 90 degrees, and it was confirmed that the DLC compound was oriented perpendicular to the film surface. In addition, the angle of the slow axis was parallel to the rotation axis of the rubbing roller, and was 45 degrees when the film longitudinal direction was 90 degrees (the film width direction was 0 degrees, and the film width direction was the reference (0 degrees) when observed from the alignment film E2 side). The obtained retardation layer 3 was a half-wave retarder at 550 nm, and its retardation was 275 nm plus (Re(550) = 275 nm), and 294 nm at 440 nm (Re(440) = 294 nm).

[0155] Composition F-3 for forming retardation layer: Discotic liquid crystal compound (A) (the above formula (6)) 80 parts by mass Discotic liquid crystal compound (B) (the above formula (7)) 20 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 5 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by Ciba Japan KK) 4 parts by mass Pyridinium salt (A) (the following formula (17)) 2 parts by mass Polymer (A) (the following formula (18)) 0.2 parts by mass Polymer (B) (the following formula (19)) 0.1 parts by mass Polymer (C) (the following formula (20)) 0.1 parts by mass Methyl ethyl ketone 211 parts by mass

[0156]

[0157]

[0158] In formula (18), the numerical value for each repeating unit represents the content (mass%) of each repeating unit relative to all repeating units. Weight average molecular weight: 23,000

[0159]

[0160] In formula (19), a = 90 and b = 10. a and b each represent the content (mass%) of each repeating unit relative to the total repeating units. Weight average molecular weight: 25,000

[0161] In formula (20), the numerical value shown for each repeating unit represents the content (mass%) of each repeating unit relative to all repeating units. Weight average molecular weight: 16,000

[0162] (Fabrication of light control device 3) In the light control device 1 of Example 1, the process of laminating the optical laminate 1 with an adhesive, peeling off the cellulose acylate film A1 / photo-alignment film E1, and laminating the retardation layer 1 was changed to the process of laminating the optical laminate 3 with an adhesive, peeling off the cellulose acylate film A2 / alignment film E2, and laminating the retardation layer 3. Except for this, a light control device 3 was fabricated in the same manner as the light control device 1 of Example 1, in which the host-guest liquid crystal layer 1 / fixing layer (adhesive) / retardation layer 3 / fixing layer (adhesive) / host-guest liquid crystal layer 2 were laminated in this order (see Figure 2).

[0163] Example 4 (Formation of Retardation Layer 4) In the method for producing the retardation layer 1 of Example 1, a high-pressure mercury lamp was used in a nitrogen atmosphere at a wavelength of 365 nm and 100 mJ / cm ２ The coating film was irradiated with ultraviolet light of 500 mJ / cm 2 while being heated to 120°C. ２ The process of irradiating the coating film with ultraviolet light of 50 mJ / cm at a wavelength of 365 nm using a high-pressure mercury lamp under a nitrogen atmosphere. ２ A retardation layer 4 was produced in the same manner as the retardation layer 1 of Example 1, except that the step of irradiating the coating film with ultraviolet light was changed to 1000 nm. Thus, an optical laminate 4 was obtained in which the cellulose acylate film A1 / photo-alignment film E1 / retardation layer 4 were laminated in this order (see FIG. 4).

[0164] The retardation layer 4 had a thickness of 4.8 μm and was a half-wave retarder at 550 nm, with Re(550)=275 nm, and also a half-wave retarder at 440 nm, with Re(440)=220 nm.

[0165] (Fabrication of light control device 4) In the light control device 1 of Example 1, the process of laminating the optical laminate 1 with an adhesive, peeling off the cellulose acylate film A1 / photo-alignment film E1, and laminating the retardation layer 1 was changed to the process of laminating the optical laminate 4 with an adhesive, peeling off the cellulose acylate film A1 / photo-alignment film E1, and laminating the retardation layer 4. Except for this, a light control device 4 was fabricated in the same manner as the light control device 1 of Example 1, in which the host-guest liquid crystal layer 1 / fixing layer (adhesive) / retardation layer 4 / fixing layer (adhesive) / host-guest liquid crystal layer 2 were laminated in this order (see Figure 2).

[0166] Example 5 (Formation of Retardation Layer 5) In the method for producing the retardation layer 1 of Example 1, a high-pressure mercury lamp was used in a nitrogen atmosphere at a wavelength of 365 nm and 100 mJ / cm ２ The coating film was irradiated with ultraviolet light of 500 mJ / cm 2 while being heated to 120°C. ２ The process of irradiating the coating film with ultraviolet light of 10 mJ / cm at a wavelength of 365 nm using a high-pressure mercury lamp under a nitrogen atmosphere. ２ A retardation layer 5 was produced in the same manner as the retardation layer 1 of Example 1, except that the step of irradiating the coating film with ultraviolet light was changed to 1000 nm. Thus, an optical laminate 5 was obtained in which the cellulose acylate film A1 / photo-alignment film E1 / retardation layer 5 were laminated in this order (see FIG. 4).

[0167] The retardation layer 5 had a thickness of 4.8 μm, and was a half-wave retarder at 550 nm, with Re(550)=275 nm, and also a half-wave retarder at 440 nm, with Re(440)=220 nm.

[0168] (Fabrication of light control device 5) In the light control device 1 of Example 1, the process of laminating the optical laminate 1 with an adhesive, peeling off the cellulose acylate film A1 / photo-alignment film E1, and laminating the retardation layer 1 was changed to the process of laminating the optical laminate 5 with an adhesive, peeling off the cellulose acylate film A1 / photo-alignment film E1, and laminating the retardation layer 5. Except for this, a light control device 5 was fabricated in the same manner as the light control device 1 of Example 1, in which the host-guest liquid crystal layer 1 / fixing layer (adhesive) / retardation layer 5 / fixing layer (adhesive) / host-guest liquid crystal layer 2 were laminated in this order (see Figure 2).

[0169] Comparative Example 1 A light control device P1 was fabricated in the same manner as the light control device 1 of Example 1, except that the retardation layer 1 was changed to a polycarbonate film 1 (PureAce GR manufactured by Teijin Limited, Re(550)=275 nm). The light control device P1 was fabricated in the same manner as the light control device 1 of Example 1, in which a host-guest liquid crystal layer 1, a fixing layer (adhesive), a polycarbonate film 1, a fixing layer (adhesive), and a host-guest liquid crystal layer 2 were laminated in this order (see FIG. 1 ). The polycarbonate film 1 was used as the retardation layer P1.

[0170] Comparative Example 2 A light control device P2 was produced in the same manner as in the light control device 2 of Example 2, except that the optically anisotropic layer 1 was changed to a polycarbonate film 2 (PureAce RM manufactured by Teijin Limited, Re(550)=140 nm, Re(440)=118 nm), in which the host-guest liquid crystal layer 1 / fixing layer (adhesive) / polycarbonate film 2 / fixing layer (adhesive) / polycarbonate film 2 / host-guest liquid crystal layer 2 were laminated in this order (see FIG. 2 ). In the configuration of the light control device P2, a laminate having a configuration of polycarbonate film 2 / fixing layer (adhesive) / polycarbonate film 2 was used as the retardation layer P2.

[0171] (Evaluation) (Softening temperature of retardation layer) The softening temperature of each of the retardation layers 1 to 5, the retardation layer P1, and the retardation layer P2 was measured. The softening temperature of the retardation layer was measured using a differential scanning calorimeter (X-DSC, manufactured by Hitachi High-Tech Science Corporation) and a thermomechanical analyzer (TMA7300, manufactured by Hitachi High-Tech Science Corporation).

[0172] For Example 1, optical laminate 1 was used, for Example 2, optical laminate 2 was used, for Example 3, optical laminate 3 was used, for Example 4, optical laminate 4 was used, and for Example 5, optical laminate 5 was used. For Comparative Example 1, retardation layer P1 was used, and for Comparative Example 2, retardation layer P2 was used. Approximately 20 mg of each of the optical laminate and retardation layer was sampled in an aluminum pan, and differential scanning calorimetry was performed at a heating rate of 10 ° C. / min and a temperature range of 25 ° C. to 725 ° C. The temperature at which the calorific value begins to change due to a baseline shift or peak, and the temperature at which the calorific value begins to change due to a baseline shift or peak, and the temperature at which the softening point begins to change due to a baseline shift or peak, were measured. 1 cm2 of the optical laminate and retardation layer were sampled, and a thermomechanical analyzer was used to perform penetration measurement from the retardation layer or optically anisotropic layer side at a heating rate of 10 ° C. / min, a probe tip diameter of 1 mm, and a temperature range of 25 ° C. to 1500 ° C. The lowest temperature at which a softening point was observed was determined as the softening temperature. In the differential scanning calorimetry, the changes in heat quantity due to the non-retardation layer and the non-optically anisotropic layer contained in the optical laminate and the retardation layer were excluded. The results are shown in Table 1 below.

[0173] (Light resistance test) The prepared light control device was subjected to sunlight collection for 1 minute using a lens with a pupil diameter equivalent to 60 mm, and the degree of fading due to deterioration in the phase difference of the light collection part was evaluated according to the following evaluation criteria. The results are shown in Table 1 below.

[0174] (Evaluation Criteria) A: Discoloration of the light-collecting portion cannot be visually discerned. B: Discoloration of the light-collecting portion can be slightly visually discerned. C: Discoloration of the light-collecting portion can be clearly visually discerned.

[0175]

[0176] (Example 6) (Camera with light control device) The light control device 1 of Example 1 was placed in front of the image sensor 33 with respect to the incident light I of the digital camera 30 shown in Fig. 3. After being exposed to sunlight outdoors, evaluation was performed according to the evaluation criteria in the light resistance test described above. No fading was visually discernible in the light collecting portion of the light control device 10, and the evaluation was A.

[0177] The disclosure of Japanese Patent Application No. 2024-036365, filed on March 8, 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A light control device comprising a plurality of liquid crystal light control layers and a retardation layer disposed between the plurality of liquid crystal light control layers, wherein the plurality of liquid crystal light control layers each contain a guest-host liquid crystal composition, and the retardation layer has a softening temperature of 180°C or higher as measured by thermal analysis.

2. The light control device according to claim 1, wherein the retardation layer contains a liquid crystal compound.

3. The light control device according to claim 2, wherein the retardation layer contains the liquid crystal compound aligned by polymerization.

4. The light control device according to claim 2, wherein the liquid crystal compound is a rod-shaped liquid crystal compound or a discotic liquid crystal compound.

5. The light control device according to claim 1, wherein the retardation layer has a softening temperature of 250° C. or higher.

6. The light control device according to claim 1, wherein the retardation layer has an Re(550) of 100 nm to 300 nm and an Re(440) of 100 nm to 300 nm.

7. The light control device according to claim 1, wherein the retardation layer is a half-wave plate for light of 550 nm and a half-wave plate for light of 440 nm.

8. The light control device according to claim 1, further comprising a fixation layer that fixes the liquid crystal light control layer and the retardation layer, the light control device having the first liquid crystal light control layer, the fixation layer, the retardation layer, the fixation layer, and the second liquid crystal light control layer in this order.

9. The light control device according to claim 1, wherein the retardation layer comprises a plurality of optically anisotropic layers and a fixation layer that fixes the plurality of optically anisotropic layers, and the light control device has a first optically anisotropic layer, the fixation layer, and a second optically anisotropic layer in this order.

10. The light control device according to claim 9, wherein the optically anisotropic layer is a quarter-wave plate for light of 550 nm and a quarter-wave plate for light of 440 nm.

11. An imaging device including the light control device according to any one of claims 1 to 10.

Images