KR101745755B1 - Optical element - Google Patents

Abstract

The present application provides an optical element and a smart blind including the optical element. The optical element of the present application can be used for a smart blind since it can suppress the light leakage phenomenon upon transmission or blocking by compensating the retardation in the thickness direction of the protective film.

Description

[0001] OPTICAL ELEMENT [0002]

The present application relates to optical elements and smart blinds.

Blinds are often used in windows to hide sunlight or to prevent them from being seen outside. Conventional blinds are made by connecting several narrow, long scaly skeletons with a line, and the scales of the blind are moved by a line to block or shrink as much sunlight as desired. In recent years, blinds having an atmosphere similar to that of cloth-like curtains have been used, and for example, decorative blinds called vertical are also known.

The present application provides optical elements and smart blinds.

Exemplary optical elements of the present application can be used as smart blinds. As used herein, the term " smart blind " may mean, for example, a functional member capable of implementing a transmission or blocking mode only in a predetermined region of a blind, as well as a front transmission and a frontal blocking mode.

FIG. 1 is a view showing an exemplary structure of a conventional smart blind. As shown in FIG. 1, each of the smart blinds is disposed such that a polarizer and a polarizing plate including a liquid crystal layer disposed on one side of the polarizer face each other. The optical characteristics of the smart blind are influenced by polarizers which are polarization components. In general, four protective films are used between the polarizers, because a protective film of a polarizer and a protective film of a liquid crystal layer are respectively present. TAC, which is most widely used as a protective film, basically has a thickness direction retardation of -50 nm, so that a thickness direction retardation of a total of -200 nm is generally expressed. Due to the retardation in the thickness direction, there is a problem due to light leakage in terms of implementation of transmission and blocking.

Exemplary optical elements of the present application include a polarizer; A 1/4 wavelength layer disposed on one side of the polarizer and including first and second regions having different phase retardation characteristics from each other, and a retardation layer disposed between the polarizer and the 1/4 wavelength layer, An optical anisotropic film having a larger retardation in the thickness direction than the sum of retardation values in the thickness direction of the protective film may be additionally included in the first and second polarizing plates, have.

In one example, the thickness direction retardation value of the protective film may be -40 to -60 nm, but is not limited thereto.

In one example, the protective film may include, but is not limited to, TAC (Tri Acetyl Cellulose). The most widely used protective film for general polarizers is TAC, and TAC has a negative retardation value.

In one example, the optically anisotropic film may be a + C plate. The retardation value in the thickness direction is defined by the following equation 1 using the difference between the refractive index in the plane direction and the refractive index in the thickness direction and the thickness of the film when n _x = n _y <n _z

[Formula 1]

R _th = d _X (n _z -n _y )

Herein, n _x is the refractive index in the x-axis direction, n _y is the refractive index in the y-axis direction, n _z is the refractive index in the thickness direction, that is, the refractive index in the z-axis direction, and d is the thickness of the film. The + C plate is a film in which the phase retardation value is almost zero and the retardation value in the thickness direction has a positive value.

In one example, the + C plate may comprise a polymeric material or a UV curable liquid crystal film, and examples of usable films include a homeotropic aligned liquid crystal film, a biaxially stretched polycarbonate (PC) film, And so on.

In another exemplary optical element of the present application, the optical element comprises a polarizer; A 1/4 wavelength layer disposed on one side of the polarizer and including first and second regions having different phase delay characteristics from each other and a retardation layer disposed between the polarizer and the 1/4 wavelength layer, The first and second polarizing plates each including a protective film of -10 nm to 10 nm may be disposed so as to face each other. In this case, the retardation value in the thickness direction of the protective film is preferably zero.

In one example, the protective film having a retardation in the thickness direction of -10 nm to 10 nm may include any one selected from unleaded COP (Cyclo-olefin) or acrylic film.

The polarizer included in the optical element is a functional element capable of extracting light oscillating in one direction from incident light while vibrating in various directions. As the polarizer, for example, a conventional polarizer such as a polyvinyl alcohol (PVA) polarizer can be used.

In one example, the polarizer may be a polyvinyl alcohol film or sheet on which a dichroic dye or iodine is adsorbed and oriented. The polyvinyl alcohol can be obtained by, for example, gelling polyvinyl acetate. Examples of the polyvinyl acetate include homopolymers of vinyl acetate; And copolymers of vinyl acetate and other monomers, and the like. As the other monomer copolymerized with vinyl acetate, there may be mentioned one kind or more of unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated sulfonic acid compounds and acrylamide compounds having an ammonium group. The degree of gelation of polyvinyl acetate may generally be from about 85 mol% to about 100 mol% or from 98 mol% to 100 mol%. The degree of polymerization of the polyvinyl alcohol used in the polarizer may generally be from about 1,000 to about 10,000 or from about 1,500 to about 5,000.

In one example, any one of the first and second regions may be an area that can convert incident light into left circularly polarized light and transmit it, and the other area may convert incident light into right circularly polarized light to be transmitted Lt; / RTI &gt;

In one example, the first and second regions may be alternately arranged with a stripe shape extending in a common direction.

In one example, the first region of the first polarizing plate may be disposed to face the first region of the second polarizing plate in the first or second aspect.

In one example, the first region of the first polarizing plate and the first region of the second polarizing plate are arranged so that the light absorption axes thereof are aligned with each other, and the second region of the first polarizing plate and the second region of the second polarizing plate And the light absorption axes may be arranged horizontally with respect to each other.

In one example, the first and second polarizing plates may be moved such that the first region of the first polarizing layer disposed opposite to the first region of the second polarizing plate faces the second region of the second polarizing plate, The first and second polarizing plates may be disposed so that the relative position of the second polarizing plate may be changed.

In one example, the quarter wave layer may comprise a liquid crystal layer comprising a polymerizable liquid crystal compound. The liquid crystal layer may contain the polymerizable liquid crystal compound in a polymerized form. As used herein, the term &quot; polymerizable liquid crystal compound &quot; may mean a compound containing a moiety capable of exhibiting liquid crystallinity, for example, a mesogen skeleton, and further containing at least one polymerizable functional group . The phrase "the polymerizable liquid crystal compound is contained in a polymerized form" may mean a state in which the liquid crystal compound is polymerized to form a skeleton such as a main chain or side chain of the liquid crystal polymer in the liquid crystal layer.

The liquid crystal layer may further contain a polymerizable liquid crystal compound in a non-polymerized state, or may further contain known additives such as a polymerizable non-liquid crystalline compound, a stabilizer, a non-polymerizable non-liquid crystalline compound or an initiator.

In one example, the polymerizable liquid crystal compound contained in the liquid crystal layer may include a polyfunctional polymerizable liquid crystal compound and a monofunctional polymerizable liquid crystal compound.

The term "multifunctional polymerizable liquid crystal compound" may mean a compound containing two or more polymerizable functional groups in the liquid crystal compound. In one example, the polyfunctional polymerizable liquid crystal compound has from 2 to 10, from 2 to 8, from 2 to 6, from 2 to 5, from 2 to 4, from 2 to 3 Or two. Further, the term "monofunctional polymerizable liquid crystal compound" may mean a compound containing one polymerizable functional group in the liquid crystal compound.

The use of the multifunctional and monofunctional polymerizable compound together can effectively control the phase delay characteristics of the liquid crystal layer and can also stably maintain the implemented phase delay characteristics such as the optical axis of the phase delay layer or the phase delay value . In this specification, the term optical axis may refer to a slow axis or a fast axis when light passes through the corresponding region.

The liquid crystal layer is formed by mixing the monofunctional polymerizable liquid crystal compound in an amount of 0 to 100 parts by weight, 1 to 90 parts by weight, 1 to 80 parts by weight, 1 part by weight To 70 parts by weight, 1 part by weight to 60 parts by weight, 1 part by weight to 50 parts by weight, 1 part by weight to 30 parts by weight or 1 part by weight to 20 parts by weight.

Within this range, the mixing effect of the polyfunctional and monofunctional polymerizable liquid crystal compound can be maximized, and the liquid crystal layer can exhibit excellent adhesion with the adhesive layer. Unless specifically stated otherwise herein, unit weight parts can mean weight ratios.

In one example, the polymerizable liquid crystal compound may be a compound represented by the following formula (1).

[Chemical Formula 1]

Wherein A is a single bond, -COO- or -OCO-, R1 to R10 are each independently selected from the group consisting of hydrogen, a halogen, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, 2, R &_lt; ₁ &gt; to R &_lt; ₁₀ &_gt; , At least one of them is -OQP or a substituent of the following formula 2, or two adjacent substituents of R ₁ to R ₅ or two adjacent substituents of R ₆ to R ₁₀ are connected to each other to form benzene substituted with -OQP , Wherein Q is an alkylene group or an alkylidene group and P is a polymerizable group such as an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group It is a functional group:

(2)

Wherein B is a single bond, -COO- or -OCO-, and R ₁₁ to R ₁₅ are each independently selected from the group consisting of hydrogen, a halogen, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, a nitro group or -OQP , At least one of R ₁₁ to R ₁₅ is -OQP, or two adjacent substituents of R ₁₁ to R ₁₅ are connected to each other to form benzene substituted with -OQP, wherein Q is an alkylene group or an alkylidene group , And P is a polymerizable functional group such as an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group.

The formation of benzene substituted with -OQP in the above two substituents in Formulas 1 and 2 means that two adjacent substituents are connected to each other to form a naphthalene skeleton substituted with -OQP as a whole have.

In the above formula (2), "-" on the left side of B may mean that B is directly connected to benzene of the formula (1).

The term "single bond" in the above formulas (1) and (2) means a case where no separate atom exists in the part represented by A or B. For example, when A is a single bond in formula (I), benzene on both sides of A may be directly connected to form a biphenyl structure.

As the halogen in the above formulas (1) and (2), chlorine, bromine or iodine can be exemplified.

The term alkyl group as used herein includes, unless otherwise specified, a linear or branched alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms or a linear or branched alkyl group having 3 to 20 carbon atoms, Or a cycloalkyl group having 3 to 16 carbon atoms or 4 to 12 carbon atoms. The alkyl group may be optionally substituted with one or more substituents.

As used herein, unless otherwise specified, the term alkoxy group may mean an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The alkoxy group may be linear, branched or cyclic. In addition, the alkoxy group may be optionally substituted with one or more substituents.

In the present specification, the term alkylene group or alkylidene group may mean an alkylene group or alkylidene group having 1 to 12 carbon atoms, 4 to 10 carbon atoms, or 6 to 9 carbon atoms unless otherwise specified. The alkylene group or alkylidene group may be linear, branched or cyclic. Also, the alkylene group or alkylidene group may be optionally substituted with one or more substituents.

The alkenyl group in the present specification may mean an alkenyl group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms unless otherwise specified. The alkenyl group may be linear, branched or cyclic. In addition, the alkenyl group may be optionally substituted with one or more substituents.

In the general formulas (1) and (2), P is preferably an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group, more preferably an acryloyloxy group or a methacryloyloxy group, And more preferably an acryloyloxy group.

Examples of the substituent which may be substituted in the specific functional group in the present invention include alkyl groups, alkoxy groups, alkenyl groups, epoxy groups, oxo groups, oxetanyl groups, thiol groups, cyano groups, carboxyl groups, acryloyl groups, methacryloyl groups, Acryloyloxy group, methacryloyloxy group, aryl group, and the like, but the present invention is not limited thereto.

The -OQP or the moiety of Formula 2, which may be present in at least one of the above Formulas 1 and 2, may be present, for example, at the position of R ₃ , R ₈ or R ₁₃ . It is also preferred that R &lt; ₃ &gt; and R &lt; _{4 &} gt ;, or R &lt; ₁₂ &gt; and R &lt; ₁₃ &gt; In addition, substituents other than -OQP or the residue of the formula (2) in the above-mentioned compound of formula (1) or the residue of formula (2) or substituents other than those forming a benzene bond to each other are, for example, hydrogen, halogen, Or a branched alkyl group, an alkoxycarbonyl group containing a straight or branched alkoxy group having 1 to 4 carbon atoms, a cycloalkyl group having 4 to 12 carbon atoms, a cyano group, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, Preferably a straight or branched alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 4 to 12 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group containing a straight-chain or branched alkoxy group having 1 to 4 carbon atoms, Cyano group.

In one example, the polymerizable liquid crystal compound may be included in the liquid crystal layer in a horizontally oriented state. As used herein, the term &quot; horizontal alignment &quot; means that the optical axis of the coating layer comprising the polymerized liquid crystal compound is in the range of about 0 degrees to about 25 degrees, about 0 degrees to about 15 degrees, about 0 degrees to about 10 degrees, About 0 degrees to about 5 degrees or about 0 degrees. In this specification, the term optical axis may refer to a fast axis or a slow axis when the incident light passes through the corresponding region.

In one example, the difference between the refractive index in the in-plane slow axis direction and the refractive index in the in-plane fast axis direction may be in the range of 0.05 to 0.2, 0.07 to 0.2, 0.09 to 0.2, or 0.1 to 0.2 in the liquid crystal layer. The refractive index in the in-plane slow axis direction means the refractive index in the direction showing the highest refractive index in the plane of the liquid crystal layer and the refractive index in the fast axis direction is the refractive index in the direction showing the lowest refractive index on the plane of the liquid crystal layer It can mean. In general, in the optically anisotropic liquid crystal layer, the fast axis and the slow axis are formed in directions perpendicular to each other. Each of the refractive indices may be a refractive index measured with respect to light having a wavelength of 550 nm or 589 nm.

The liquid crystal layer may also have a thickness of about 0.5 占 퐉 to 2.0 占 퐉 or about 0.5 占 퐉 to 1.5 占 퐉.

The liquid crystal layer having the relationship of the refractive index and the thickness can realize the phase delay characteristic suitable for the application to which it is applied. In one example, the liquid crystal layer having the refractive index relationship and thickness may be suitable for a smart blind.

The liquid crystal layer may be formed so as to divide incident light, for example, light incident through the polarizer, into two or more kinds of lights having different polarization states. For this purpose, for example, the liquid crystal layer may include first and second regions having different phase delay characteristics. Herein, the phase delay characteristics of the first region and the second region are different from each other when the first and second regions are equal to or different from each other in a state where the first and second regions are all regions having phase delay characteristics Direction and the phase delay values are different from each other and a case where the optical axis is formed in a different direction with the same phase delay value. In another example, the phase delay characteristics of the first and second regions are different from each other in that any one of the first and second regions is a region having a phase delay characteristic and the other region is an optically isotropic Region can also be included. Examples of such a case include a region including both the region where the liquid crystal layer is formed and the region where the liquid crystal layer is not formed. The phase delay characteristics of the first or second region can be controlled by, for example, adjusting the alignment state of the liquid crystal compound, the refractive index relationship of the liquid crystal layer, or the thickness of the liquid crystal layer.

In one example, the liquid crystal layer may have an orientation film formed on either side thereof.

In one example, the alignment layer may include a photo alignment layer containing a photo alignment compound. The polarizer may be formed by coating the polarizing material including the polymerizable liquid crystal compound and the dichroic dye on the upper part of the photo alignment layer. The term &quot; photo-alignment compound &quot; as used herein refers to a compound that is orientationally ordered in a predetermined direction through irradiation of light or the like, and causes the adjacent liquid crystal compound to interact with a predetermined direction &Lt; / RTI &gt; The photo-aligning compound in the orientation layer may be aligned so as to have a directionality by an ancestor of the linearly polarized light. The photo directing compound may be a monomolecular compound, a monomeric compound, an oligomeric compound or a polymeric compound.

When the oriented compound is a polymeric compound, the compound may have a number average molecular weight of, for example, from about 10,000 g / mol to about 500,000 g / mol, but is not limited thereto.

The precursor forming the orientation layer or the orientation layer may further comprise a photoinitiator in addition to the photo-orientable compound. The photoinitiator can be used without particular limitation, for example, as long as it can induce a free radical reaction by an anion of light. As such a photoinitiator, an alpha hydroxy ketone compound, an alpha amino ketone compound, a phenyl glyoxylate compound or an oxime ester compound can be exemplified, and for example, an oxime europium compound can be used. The proportion of the photoinitiator in the precursor is not particularly limited and may be included to such an extent as to induce an appropriate reaction.

In one example, the orientation of the photo-alignment layer may be performed to include first and second orientation regions oriented in different directions, and the orientation process may be performed through irradiation of linearly polarized light, But is not limited to. In the alignment process, at least some regions of the alignment layer may be simultaneously or sequentially exposed to linearly polarized light polarized in mutually different directions.

In one example, the optical element may have at least two protective films between the polarizer and the quarter wavelength layer. The protective film may be present on the polarizer and the quarter wavelength layer, respectively.

In one example, the polarizer may further comprise a substrate layer formed on one side, in which case a polarizer is formed on the substrate layer, and a 1/4 wavelength layer may be formed on the polarizer have.

As the base layer, for example, a glass base layer or a plastic base layer can be used. Examples of the plastic substrate layer include a cellulose resin such as TAC (triacetyl cellulose) or DAC (diacetyl cellulose); COP (cyclo olefin polymer) such as norbornene derivatives; Polyolefins such as polyethylene (PE) or polypropylene (PVP), polyvinyl alcohol (PVA), polyether sulfone (PES), polyetheretherketone (PEEK) polyetherimide, polyetherimide, polyetheretherketone (PEN), polyetheretherketone (PEN), polyethylenemaphthatate (PEN), polyetheretherketal (PET), polyimide (PI), polysulfone (PSF) or fluororesin.

The present application also relates to a smart blind comprising the optical element.

The optical element of the present application can be used for a smart blind since it can suppress the light leakage phenomenon upon transmission or blocking by compensating the retardation in the thickness direction of the protective film.

The concrete types, structures, and components of the smart blind are not particularly limited, so long as the optical element is included, all contents known in the art can be applied.

The optical element of the present application can be used for a smart blind since it can suppress the light leakage phenomenon upon transmission or blocking by compensating the retardation in the thickness direction of the protective film.

1 is a view showing an example of a conventional smart blind.
2 is a diagram showing the transmission color characteristics of a conventional smart blind.
3 is a diagram illustrating the transmission color characteristics of an exemplary smart blind of the present application.
4 is a diagram illustrating the transmission color characteristics of an exemplary smart blind of the present application.

Hereinafter, the present invention will be described in more detail with reference to the embodiments of the present invention and the comparative examples not in accordance with the present invention, but the scope of the present invention is not limited by the following examples.

Comparative Example  One

A PVA polarizer coated on both sides with a TAC protective film was prepared and a 1/4 wavelength layer coated on one side with a TAC protective film was prepared and then the first and second polarizing plates So that the smart blind of Comparative Example 1 was manufactured. The transmission color characteristics of the smart blind of Comparative Example 1 are shown in Fig.

Example  One

The Smart Blind of Example 1 was prepared by placing a + C plate having a thickness direction retardation value of 330 nm between the polarizing plates arranged to face each other in Comparative Example 1. The transmission color characteristics of the smart blind of Example 1 are shown in Fig.

Example  2

The Smart Blind of Example 2 was manufactured by replacing the TAC protective film between the PVA polarizer and the 1/4 wavelength plate of the polarizing plate with an acrylic film having a thickness direction retardation value of -10 nm to 10 nm. The transmission color characteristics of the smart blind of Example 2 are shown in Fig.

Claims (16)

A polarizer; A 1/4 wavelength layer disposed on one side of the polarizer and including first and second regions having different phase retardation characteristics from each other, and a retardation layer disposed between the polarizer and the 1/4 wavelength layer, And an optical anisotropic film further comprising an optically anisotropic film having a larger retardation in the thickness direction than the sum of retardation values in the thickness direction of the protective film, wherein the first and second polarizers each include a protective film, A smart blind comprising a device,
Wherein the first and second regions of the first and second polarizing plates are alternately arranged with a stripe shape extending in a common direction with respect to each other, And the other region is an area that can convert incident light into right circularly polarized light and transmit it,
The first region of the first polarizing plate is disposed to face the first region of the second polarizing plate, and the first region of the first polarizing plate and the first region of the second polarizing plate are arranged so that the light absorption axes thereof are horizontally aligned with each other And the second region of the first polarizing plate and the second region of the second polarizing plate are arranged so that the light absorption axes are mutually horizontal,
The first region of the first polarizing plate being disposed to face the first region of the second polarizing plate so as to be opposed to the second region of the second polarizing plate so that the relative positions of the first and second polarizing plates The first and second polarizing plates are arranged so that the first and second polarizing plates can be changed,
Wherein the smart blind implements a transmission mode and a blocking mode and has a transmissivity of 0.07 or less measured at an azimuth angle of 0 to 360 degrees and does not include a liquid crystal cell between the first and second polarizers. A polarizer; A 1/4 wavelength layer disposed on one side of the polarizer and including first and second regions having different phase delay characteristics from each other and a retardation layer disposed between the polarizer and the 1/4 wavelength layer, And a first and a second polarizing plates each including a protective film of -10 nm to 10 nm arranged so as to face each other,
Wherein the first and second regions of the first and second polarizing plates are alternately arranged with a stripe shape extending in a common direction with respect to each other, And the other region is an area that can convert incident light into right circularly polarized light and transmit it,
The first region of the first polarizing plate is disposed to face the first region of the second polarizing plate, and the first region of the first polarizing plate and the first region of the second polarizing plate are arranged so that the optical absorption axes thereof are horizontally aligned with each other And the second region of the first polarizing plate and the second region of the second polarizing plate are arranged so that the light absorption axes are mutually horizontal,
The first region of the first polarizing plate being disposed to face the first region of the second polarizing plate so as to be opposed to the second region of the second polarizing plate so that the relative positions of the first and second polarizing plates The first and second polarizing plates are arranged so that the first and second polarizing plates can be changed,
Wherein the smart blind implements a transmission mode and a blocking mode and has a transmissivity of 0.07 or less measured at an azimuth angle of 0 to 360 degrees and does not include a liquid crystal cell between the first and second polarizers. delete delete delete delete The smart blind according to claim 1, wherein the thickness direction retardation value of the protective film is from -40 to -60 nm. The smart blind according to claim 1, wherein the protective film comprises TAC (Tri Acetyl Cellulose). The smart blind according to claim 1, wherein the optically anisotropic film is a + C plate. 10. The smart blind according to claim 9, wherein the + C plate comprises a polymer material or a UV curable liquid crystal film. The smart blind according to claim 2, wherein the protective film having a retardation in the thickness direction of -10 nm to 10 nm comprises any one selected from unleaded COP (Cyclo-olefin) or acrylic film. The smart blind according to claim 1 or 2, wherein the 1/4 wavelength layer is a liquid crystal layer containing a polymerizable liquid crystal compound. 13. The polymerizable liquid crystal compound according to claim 12, wherein the polymerizable liquid crystal compound is a smart blind:
[Chemical Formula 1]

Wherein A is a single bond, -COO- or -OCO-, and R ₁ to R ₁₀ are each independently selected from the group consisting of hydrogen, a halogen, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, a nitro group, -OQP Wherein at least one of R ₁ to R ₁₀ is -OQP or a substituent of the following formula 2 or two adjacent substituents of R ₁ to R ₅ or two adjacent substituents of R ₆ to R ₁₀ are And Q is an alkylene group or an alkylidene group, P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, Or a methacryloyloxy group:
(2)

Wherein B is a single bond, -COO- or -OCO-, and R ₁₁ to R ₁₅ are each independently selected from the group consisting of hydrogen, a halogen, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, a nitro group or -OQP , At least one of R ₁₁ to R ₁₅ is -OQP, or two adjoining substituents of R ₁₁ to R ₁₅ are connected to each other to form benzene substituted with -OQP, Q is an alkylene group or an alkylidene group, P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group. The smart blind according to claim 12, wherein the polymerizable liquid crystal compound is included in the liquid crystal layer in a horizontally oriented state. The smart blind according to claim 1 or 2, wherein at least two protective films are present between the polarizer and the quarter wavelength layer. delete

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