WO2015047013A1 - Optical device - Google Patents

Abstract

The present invention relates to an optical device and a use of the optical device. An exemplary optical device can realize a smart blind having excellent transmission and block characteristics at the side surface as well as the front surface even without a phase retardation film, using a polarizing layer having patterned polarization characteristics through a guest and host type dye layer containing a polymerizable liquid crystal compound and a dichromatic dye. The optical device can be applied to various light modulation devices, such as a smart blind, a smart window, a window protection film, a flexible display device, an active retarder for 3D image display, and a viewing angle control film.

Description

Optical element

The present application relates to an optical element and a smart blind.

Smart blinds are blinds that can control the transmittance of sunlight, and are also called smart windows, electronic curtains, variable transmittance glass, or dimmed glass.

For example, the smart blind may include a light transmittance adjusting layer capable of adjusting the amount of light transmitted, and a driving circuit configured to apply a signal to and control the light transmittance adjusting layer. The smart blinds configured as described above may vary the contrast by preventing light from being transmitted or transmitted through the entire glass according to the applied voltage. However, the above-described method has a problem in that the power supply system structure is complicated because a separate external power must be supplied to drive the smart blind.

In recent years, a technique for manufacturing smart blinds by combining a polarizing plate and a retardation film so as not to require an external power source like Patent Document 1 (Korean Patent Laid-Open Publication No. 2004-0004138) has been developed. As the retardation film, a liquid crystal film which is patterned mainly with regions having optical axes in different directions is used. In this case, optical characteristic unevenness is caused due to a slight optical axis deviation in the side surface, thereby realizing uniform visibility. There is no problem.

The present application provides an optical element and a smart blind.

The exemplary optical element may include a first polarization layer and a second polarization layer disposed to face each other. The first and second polarization layers may each include a first region having an absorption axis formed in a first direction and a second region having an absorption axis formed in a second direction different from the first direction. In addition, at least one of the first and second polarization layers may be a dye layer including a polymerizable liquid crystal compound and a dichroic dye. Such a dye layer is called a guest host type polarizing element. For example, dichroic dyes are arranged together according to the arrangement of the polymerizable liquid crystal compound to absorb light parallel to the alignment direction of the dye and to transmit vertical light. It can exhibit an isotropic light absorption effect.

Exemplary optical elements can be used, for example, as smart blinds. In the present application, the “smart blind” may refer to a functional member capable of implementing a transmission or blocking mode only at a predetermined portion of the blind as well as the front transmission and front blocking modes.

In the present application, the “polarization layer” may mean a functional layer having an transmission axis formed in one direction and exhibiting anisotropic transmission characteristics with respect to incident light. For example, the polarizing layer may have a function of transmitting light vibrating in one direction from incident light vibrating in various directions and absorbing light vibrating in the other direction.

The first and second cannula layers can be arranged such that their relative positions with respect to each other can be varied. As will be described later, the optical element may adjust the amount of light transmission based on the change in relative position of the first and second polarization layers. FIG. 1A illustrates a first polarization layer 101 including first and second regions 1011 and 1012 and a second polarization layer 102 including first and second regions 1021 and 1022. The optical elements which are disposed to face each other are exemplarily shown, and FIG. 1B shows an optical state in which the first polarizing layer 101 and the second braided layer 102 are changed relative to each other. The device is shown by way of example.

The first and second polarizing layers each have a first region having an absorption axis formed in a first direction and an absorption axis formed in a second direction different from the first direction, for example, a direction perpendicular to the first direction. It may include a second region. The first regions 1011 and 1021 and the second regions 1021 and 1022 of the first and second polarization layers have stripe shapes extending in a common direction with each other, for example, as shown in FIGS. 2 and 3. Can be arranged alternately. The stripe-shaped spacing and pitch are not particularly limited and may be appropriately selected depending on the intended use of the optical element.

For example, as shown in FIG. 1A, the optical element is disposed in a first state in which the first region 1011 of the first polarization layer and the first region 1021 of the second polarization layer face each other. Can be. In this case, for example, the optical device may be disposed such that absorption axes ↔ of the first region 1011 of the first polarization layer and the first region 1021 of the second polarization layer are parallel to each other. The absorption axes ↔ of the second region 1012 of the first polarization layer and the second region 1022 of the second polarization layer may be disposed to be parallel to each other. In this case, the optical device may transmit the polarized light in the direction parallel to the absorption axis of the first and second polarization layers facing each other in the incident light.

For example, as shown in FIG. 1B, the optical element includes a first region 1011 of the first polarization layer disposed to face the first region 1021 of the second polarization layer. Relative positions of the first and second polarization layers may be changed to move to a second state facing the second region 1022 of the polarization layer. The absorption axes ↔ of the first region 1011 of the first polarizing layer and the second region 1022 of the second polarizing layer may be perpendicular to each other. In this case, the optical element may block incident light because the absorption axis ↔ between the regions of the first and second polarizing layers is perpendicular to each other.

As described above, the first and second polarization layers may be any one of the first and second polarization layers may be the guest host dye layer, or each of the first and the second polarization layers may be the guest host dye layer. . When one of the first and second polarization layers is a guest host dye layer, the other polarization layer may be a combination of a polarizer having a transmission axis formed in one direction and a patterned retardation film. However, it is preferable that both of the first and second polarization layers are guest host dye layers in terms of implementing smart blinds having excellent transmission and blocking characteristics as intended by the present application.

The guest host dye layer may be, for example, a coating layer of a polarizing material including a polymerizable liquid crystal compound and a dichroic dye. Therefore, the optical device can be manufactured simply and continuously in a roll-to-roll process, and the thickness of the device can be reduced by simplifying the structure.

In the present application, the "polymerizable liquid crystal compound" may mean a compound containing a site capable of exhibiting liquid crystallinity, for example, a mesogen skeleton, and the like, and including one or more polymerizable functional groups. The polymerizable liquid crystal compound may be included in the polarizing layer, for example, in a polymerized state. In the present application, "the polymerizable liquid crystal compound is included 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 a side chain of the liquid crystal polymer in the polarizing layer.

As a polymerizable liquid crystal compound, the compound represented by following formula (1) can be used, for example.

[Formula 1]

In Formula 1, A is a single bond, -COO- or -OCO-, and R ₁ to R ₁₀ are each independently hydrogen, halogen, alkyl group, alkoxy group, alkoxycarbonyl group, cyano group, nitro group, -OQP or Substituent of Formula 2, wherein at least one of R ₁ to R ₁₀ is -OQP or a substituent of Formula 2, two adjacent substituents of R ₁ to R ₅ or two adjacent substituents of R ₆ to R ₁₀ Connected to each other to form a benzene substituted with -OQP, wherein Q is an alkylene group or an alkylidene group, and P is an alkenyl group, epoxy group, cyano group, carboxyl group, acryloyl group, methacryloyl group, acrylo Polymerizable functional groups such as a monooxy group or a methacryloyloxy group:

[Formula 2]

In Formula 2, B is a single bond, -COO- or -OCO-, and R ₁₁ to R ₁₅ are each independently hydrogen, halogen, alkyl group, alkoxy group, alkoxycarbonyl group, cyano group, nitro group or -OQP. , R ₁₁ to R ₁₅ or at least one of which is -OQP, R ₁₁ to R ₁₅ substituents are 2 are connected to each other and Q is an alkylene group or an alkylidene group in, and the forming a benzene substituted with -OQP adjoining and , P is a polymerizable functional group such as alkenyl group, epoxy group, cyano group, carboxyl group, acryloyl group, methacryloyl group, acryloyloxy group or methacryloyloxy group.

In Formulas 1 and 2, adjacent two substituents may be linked to each other to form benzene substituted with -OQP, which may mean that two adjacent substituents are connected to each other to form a naphthalene skeleton substituted with -OQP as a whole. have.

"-" Of the left side of B in Formula 2 may mean that B is directly connected to the benzene of Formula 1.

In Formulas 1 and 2, the term “single bond” refers to a case in which a separate atom is not present in a portion represented by A or B. For example, when A is a single bond in Formula 1, benzene on both sides of A may be directly connected to form a biphenyl structure.

As the halogen in Chemical Formulas 1 and 2, chlorine, bromine or iodine may be exemplified.

In the present application, unless otherwise specified, the term alkyl group is a straight or branched chain 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 3 to 20 carbon atoms, It may mean 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.

In the present application, 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, unless otherwise specified. The alkoxy group may be linear, branched or cyclic. In addition, the alkoxy group may be optionally substituted with one or more substituents.

In addition, in the present application, 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. In addition, the alkylene group or alkylidene group may be optionally substituted with one or more substituents.

In addition, an alkenyl group in the present application 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 Formulas 1 and 2, P is preferably acryloyl group, methacryloyl group, acryloyloxy group or methacryloyloxy group, more preferably acryloyloxy group or methacryloyloxy group, More preferably, it may be an acryloyloxy group.

Substituents that may be substituted with specific functional groups in the present application include alkyl, alkoxy, alkenyl, epoxy, oxo, oxetanyl, thiol, cyano, carboxyl, acryloyl, methacryloyl, Acryloyloxy group, methacryloyloxy group or an aryl group may be exemplified, but is not limited thereto.

The polymerizable liquid crystal compound may be included in the polarizing layer, for example, in a horizontally routed state. In the present application, the "horizontal alignment" means that the optical axis of the polarizing layer containing the polymerized liquid crystal compound is about 0 degrees to about 25 degrees, about 0 degrees to about 15 degrees, and about 0 degrees to about 10 degrees with respect to the plane of the polarizing layer. It may mean a case having an inclination angle of about 0 degrees to about 5 degrees or about 0 degrees.

As used herein, the term "dye" may refer to a material capable of intensively absorbing and / or modifying light in at least a part or the entire range within a visible light region, for example, in the wavelength range of 400 nm to 700 nm. "Active dye" may mean a material capable of anisotropic absorption of light in at least part or the entire range of the visible light region.

As the dichroic dye, for example, a known dye known to be capable of forming a so-called guest host polarizing element, for example, a known dye known to have a property that can be arranged according to the orientation of the polymerizable liquid crystal compound is selected. Can be used. As such a dichroic dye, for example, a known dye such as an azo dye or an anthraquinone dye can be used, and specifically, an azo dye F355 (registered trademark), F357 (registered trademark) or F593 (registered trademark) ( Nippon Kankoh Shikiso kenkyusho Ltd) and the like, and dyes of a kind known to exhibit the same effect as the above may be used, but are not limited thereto.

The dichroic ratio of the dichroic dye may be appropriately selected within a range that does not impair the desired physical properties. In the present application, the dichroic ratio may mean a value obtained by dividing absorption of polarization parallel to the long axis direction of the dichroic dye by absorption of polarization parallel to the direction perpendicular to the long axis direction. The dichroic dye may have a dichroic ratio of, for example, 5 or more, 6 or more or 7 or more. The dichroic dye is, for example, the dichroic ratio at least in part or at any wavelength within the wavelength range of the visible region, for example within the wavelength range of about 380 nm to 700 nm or about 400 nm to 700 nm. Can be satisfied. The upper limit of the dichroic ratio may be, for example, about 20 or less, 18 or less, 16 or less, or about 14 or less.

As described above, the optical element is uniform in both front and side surfaces by using the first and second polarization layers whose polarization characteristics are patterned using a guest host type dye layer containing a polymerizable liquid crystal compound and a dichroic dye. Smart blinds exhibit polarization characteristics and excellent transmission and blocking characteristics.

On the other hand, Figure 4 illustrates the structure of a smart blind using a combination of a conventional polarizing plate and a liquid crystal film by way of example. In the case of the smart blind of FIG. 4, the patterned retardation film 402 patterned into polarizing layers 401 and 404 having transmission axes formed in one direction as a whole and regions having optical axes ↔ in different directions from each other. And a structure in which polarizing units including 403 are disposed to face each other. In the case of the smart blind of Figure 4, the polarization characteristics of the light incident to the optical element is adjusted according to the optical axis change of the patterned retardation film, in this case the optical axis deviation occurs when observed from the side to give a uniform polarization characteristics from the side There is a problem that is difficult to achieve, because of this, it is difficult to implement a uniform luminous sense from the side, that is, the luminous sensitivity is different depending on the viewing direction. On the other hand, in the optical device of the present application, since the polarization characteristics of the incident light may be adjusted according to the absorption axis patterned on the polarization layer itself, the optical elements may exhibit uniform polarization characteristics in terms of the light.

The optical element may further include an alignment film present on one surface of the first and second polarization layers. 5 exemplarily shows an alignment film 501 having alignment regions oriented in different directions and a guest host type dye layer 502 present on the alignment film.

As the alignment film, any kind can be used as long as the alignment of the polymerizable liquid crystal compound in the adjacent polarizing layer can be appropriately controlled. For example, it is a contact alignment film such as a rubbing alignment film, or a photoalignment film compound is included. For example, an alignment film known to be able to exhibit orientation characteristics by a non-contact method such as irradiation of linearly polarized light can be used.

As an alignment film, the photo-alignment film containing a photo-alignment compound can be used, for example. In the present application, the term photo-orientation compound may refer to a compound which is aligned in a predetermined direction through irradiation of light and orientates adjacent liquid crystal compounds and the like in the alignment direction in a predetermined direction. The alignment compound may be a monomolecular compound, a monomeric compound, an oligomeric compound, or a high molecular compound.

The photoalignable compound may be a compound including a photosensitive moiety. Various photo-alignment compounds that can be used for the alignment of the liquid crystal compound are known. Photo-alignment compounds include, for example, compounds aligned by trans-cis photoisomerization; Compounds aligned by photo-destruction, such as chain scission or photo-oxidation; Compounds ordered by photocrosslinking or photopolymerization such as [2 + 2] addition cyclization ([2 + 2] cycloaddition), [4 + 4] addition cyclization or photodimerization; Compounds aligned by photo-Fries rearrangement or compounds aligned by ring opening / closure reaction may be used. As the compound aligned by trans-cis photoisomerization, for example, azo compounds or stilbenes, such as sulfated diazo dyes or azo polymers, may be exemplified. And, as the compound aligned by photolysis, cyclobutane tetracarboxylic dianhydride (cyclobutane-1,2,3,4-tetracarboxylic dianhydride), aromatic polysilane or polyester, polystyrene or polyimide and the like can be exemplified. In addition, as a compound aligned by photocrosslinking or photopolymerization, a cinnamate compound, a coumarin compound, a cinnanam compound, a tetrahydrophthalimide compound, a maleimide compound , Benzophenone compounds, diphenylacetylene compounds, compounds having chalconyl residues (hereinafter referred to as chalconyl compounds) or compounds having anthracenyl residues (hereinafter referred to as anthracenyl compounds) as photosensitive residues; This may be exemplified, and examples of the compounds aligned by the optical freeze rearrangement include aromatic compounds such as benzoate compounds, benzoamide compounds, and methacrylamidoaryl methacrylate compounds. It may be exemplified, the compound aligned by the ring-opening / ring-closure reaction, such as a spiropyran A [4 + 2] π electron system ([4 + 2] π electronic system), but may be exemplified by compounds such as sorting by a ring opening / ring-closure reaction of, without being limited thereto.

The photo-alignment compound may be a monomolecular compound, a monomeric compound, an oligomeric compound, or a high molecular compound, or may be in the form of a blend of the photo-alignment compound and the polymer. The oligomeric or polymeric compound as described above may have a residue derived from the above-described photoalignable compound or a photosensitive residue described above in the main chain or in the side chain.

Polymers having residues or photosensitive residues derived from photo-alignment compounds or that can be mixed with the photo-alignment compounds include polynorbornene, polyolefins, polyarylates, polyacrylates, poly (meth) acrylates, poly Examples include mead, poly (amic acid), polymaleimide, polyacrylamide, polymethacrylamide, polyvinyl ether, polyvinyl ester, polystyrene, polysiloxane, polyacrylonitrile or polymethacrylonitrile It may be, but is not limited thereto.

Polymers that may be included in the oriented compound include, for example, polynorbornene cinnamate, polynorbornene alkoxy cinnamate, polynorbornene allylyloxy cinnamate, polynorbornene fluorinated cinnamate, polynorbornene chlorinated cinnamate or Polynorbornene discinnamate and the like can be exemplified, but is not limited thereto.

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

The precursor layer or precursor forming the alignment layer may include a photoinitiator in addition to the photoalignable compound. As a photoinitiator, if the thing which can induce free radical reaction by the ancestor of light can be used without a restriction | limiting in particular, for example. As such a photoinitiator, an alpha hydroxy ketone compound, an alpha amino ketone compound, a phenyl glyoxylate compound, an oxime ester compound, etc. can be illustrated, for example, an oxime ester compound can be used. The proportion of photoinitiator in the precursor is not particularly limited and may be included to such an extent that an appropriate reaction can be induced.

The alignment of the photoalignment layer may be performed to include first and second alignment regions oriented in different directions, and the alignment process may be performed through irradiation of linearly polarized light. At least some regions of the alignment layer may be simultaneously or sequentially exposed to linearly polarized light polarized in different directions in the alignment process.

The optical element may further include a base layer present on either side of the first and second polarization layers. When the optical element further includes an alignment layer, the alignment layer and the polarizing layer may be sequentially formed on the base layer. As a base material layer, a well-known base material can be used without a restriction | limiting in particular. As the base layer, for example, inorganic films such as glass films, crystalline or amorphous silicon films, quartz or ITO (Indium Tin Oxide) films, plastic films and the like can be used. As the base material layer, an optically anisotropic substrate such as an optically isotropic substrate or a retardation layer can be used.

Examples of the plastic substrate include triacetyl cellulose (TAC); COP (cyclo olefin copolymer) such as norbornene derivatives; Poly (methyl methacrylate); PC (polycarbonate); PE (polyethylene); PP (polypropylene); PVA (polyvinyl alcohol); DAC (diacetyl cellulose); Pac (Polyacrylate); PES (poly ether sulfone); PEEK (polyetheretherketon Substrates including polyphenylsulfone (PPS), polyetherimide (PEI); polyethylenemaphthatlate (PEN); polyethyleneterephtalate (PET); polyimide (PI); polysulfone (PSF); polyarylate (PAR) or amorphous fluorine resin The substrate layer may include a coating layer of a silicon compound such as gold, silver, silicon dioxide or silicon monoxide, or a coating layer such as an antireflection layer, as necessary.

The present application also relates to the use of the optical element. As described above, the optical element may adjust the light transmission amount based on the change in the relative position of the first and second polarization layers, and may switch between the transmission mode and the blocking mode, for example. In addition, the optical element uses a guest host type dye layer containing a polymerizable liquid crystal compound and a dichroic dye, and uses a polarizing layer in which polarization characteristics are patterned. This smart blind can be implemented. Such an optical element can be used, for example, as an optical modulation device. The optical modulation device may include, but is not limited to, a smart blind, a smart window, a window protective film, a flexible display device, an active retarder for displaying 3D images, a viewing angle adjusting film, and the like. The manner of configuring the optical modulation device with the above is not particularly limited, and a conventional manner may be applied as long as the optical element is used.

The optical device of the present application uses a guest host type dye layer including a polymerizable liquid crystal compound and a dichroic dye as a polarizing layer in which polarization characteristics are patterned, thereby transmitting and blocking from the front as well as the side without a separate retardation film. Smart blinds with excellent characteristics can be implemented. Such an optical device may be applied to various optical modulation devices such as, for example, smart blinds, smart windows, window shields, flexible display devices, active retarders for viewing 3D images, or viewing angle adjustment films.

1 exemplarily shows an optical element of the present application.

2 to 3 exemplarily illustrate the first and second polarizing layers, respectively.

4 exemplarily shows a conventional smart blind.

5 exemplarily shows an alignment layer and a guest host type dye layer.

6 shows an image of a first polarizing layer prepared in Example 1. FIG.

7 shows a front image of the blocking mode (a) and the transmission mode (b) of the optical element of Example 1. FIG.

8 shows side images of the blocking mode (a) and the transmission mode (b) of the optical element of Example 1. FIG.

9 shows side images of the blocking mode (a) and the transmission mode (b) of the optical element of Comparative Example 1. FIG.

10 shows the principle of measuring color change in terms of Evaluation Example 1. FIG.

11 shows measurement results of side color changes in transmission modes of the optical elements of Example 1 and Comparative Example 1. FIG.

12 shows measurement results of side color changes in blocking modes of the optical devices of Example 1 and Comparative Example 1. FIG.

Hereinafter, the present invention will be described in more detail through examples according to the present invention, but the scope of the present invention is not limited by the following examples.

Example 1

The composition for forming a photo-alignment film on one surface of the glass was coated so that the thickness after drying was about 1,000 mm 3, and dried in an oven at 80 ° C. for 2 minutes. As the composition for forming the photo-alignment film, a composition prepared by dissolving 5-norbornene-2-methylcinnamate (manufactured by LG Chemical) in a toluene solvent so as to have a solid content concentration of 2 wt% was used.

Subsequently, the dried photo-alignment film-forming composition was subjected to alignment treatment according to the method disclosed in Korean Patent Application No. 2010-0009723 to form a photo-alignment film including first and second alignment regions oriented in different directions. Specifically, a pattern mask having a light transmitting portion and a light blocking portion having a width of about 450 μm and a light blocking portion alternately formed up and down and left and right are positioned on the dried composition, and different from each other on the pattern mask. The polarizing plate in which two regions which transmit polarization were formed was located. Thereafter, while moving the glass on which the photo-alignment layer is formed at a speed of about 3 m / min, UV (300 mW / cm ² ) is applied to the composition for forming the photo-alignment layer through the polarizing plate and the pattern mask for about 30 seconds. Irradiation was carried out for alignment treatment. Subsequently, the polarizing composition (G241: LC242 = 1: 20 (parts by weight)) containing a dichroic dye (G241, Nagase Co., Ltd.) and a polymerizable liquid crystal compound (LC 242, BASF Co., Ltd.) was applied on the alignment-treated alignment layer. After coating to have a dry thickness of 1 μm, the lower alignment layer is oriented according to the alignment, and then irradiated with ultraviolet (300 mW / cm ² ) for about 10 seconds to crosslink and polymerize the liquid crystal, depending on the alignment of the lower photoalignment film. The first polarizing layer was manufactured by forming a polarizing material layer in which first and second regions having absorption axes perpendicular to each other were formed. 6 shows an image of a first polarizing layer prepared in Example 1. FIG.

Next, after the second polarizing layer was manufactured by the same method as the method of manufacturing the first polarizing layer, the first and second polarizing layers were disposed to face each other to manufacture a smart blind.

The absorption modes of the regions of the first and second polarizing layers facing each other are arranged parallel to each other to implement a white mode, and the absorption axes of the respective regions of the first and second polarizing layers facing each other perpendicular to each other. The black mode is implemented by changing the relative position of the second polarization layer. 7 shows a front image of the blocking mode (a) and the transmission mode (b) of the smart blind of Example 1. FIG. 8 shows an image of the blocking mode (a) and the transmission mode (b) of the smart blind of Example 1, viewed from the side in the range of about 30 ° to 50 ° from the front. As shown in FIG. 7 and FIG. 8, the smart blind of Example 1 exhibits uniform polarization characteristics even when observed from the front as well as the front side, and shows excellent transmission and blocking characteristics as a whole.

Comparative Example 1

On the polarizing layer having the absorption axis formed in one direction, the first polarized light is formed by stacking 1/4 wave plates alternately arranged with each other having a stripe shape in which the first and second regions in which the optical axes are perpendicular to each other extend in a common direction. The unit was prepared. Next, the second polarizing unit was manufactured by the same method as the manufacturing method of the first polarizing unit. As the polarizing layer, an iodine-dyed PVA stretched film (manufactured by LG Chemical) was used, and as a quarter wave plate, a polymerizable liquid crystal compound (LC 242, BASF Co., Ltd.) was formed on the photoalignment film prepared in Example 1 above. After the liquid crystal composition comprising a) to be applied to a dry thickness of about 1㎛, orientated according to the alignment of the lower alignment layer, and irradiated with ultraviolet (300mW / cm ² ) for about 10 seconds to prepare a cross-linking and polymerization of the liquid crystal One liquid crystal film was used.

Next, the first and second polarizing units are disposed such that the quarter wave plates of the first and second polarizing units face each other, but the absorption axes of the polarizing layers of the first and second polarizing units are perpendicular to each other, and thus the comparative example is arranged. A smart blind of 1 was prepared.

The optical axes of the respective quarter wave plates of the first and second polarizing units are arranged to be parallel to each other to implement a white mode. The black mode is implemented by changing the relative positions of the second polarization units to be perpendicular to each other. FIG. 9 shows an image of the blocking mode (a) and the transmission mode (b) of the smart blind of Comparative Example 1 observed from the front side in the range of about 30 ° to 50 °. As shown in FIG. 9, when the smart blind of Comparative Example 1 is observed from the side, it may be confirmed that uniform polarization characteristics cannot be obtained due to the optical axis deviation, and thus, it is impossible to implement uniform luminous visibility from the side.

Evaluation Example 1. Observation of Color Change in Side

The optical device manufactured in Example 1 and Comparative Example 1 is arranged to implement the above-described white mode or black mode on a BLU (Black light Unit), and the ELDIM equipment is used to FIG. 10. As shown, the color change of the optical device was measured while rotating 360 ° at an incident angle of 50 °, and the results are shown in FIGS. 11 to 12 and Table 1 below. In Table 1 below, Δx means the difference between the maximum value and the minimum value of the x coordinate, and Δy means the difference between the maximum value and the minimum value of the y coordinate.

Table 1 Transmission mode (white mode) Black mode Δx △ y Δx △ y Example 1 0.024 0.042 0.048 0.086 Comparative Example 1 0.195 9.160 0.103 0.118

 As shown in FIGS. 11 to 12 and Table 1, in the case of Comparative Example 1 using a liquid crystal film and a polarizing plate in combination, it can be confirmed that the color change is larger depending on the side view than in Example 1, From Comparative Example 1 it can be seen that it is difficult to implement a uniform luminous in terms of. In particular, as shown in (b) of Figure 9, Comparative Example 1 can be seen that the yellow and blue, not showing a uniform color when observing the transmission mode (white mode) from the side, As shown in a), in the case of Comparative Example 1, the change in color from yellow to blue occurs due to rotation in the white mode.

Claims (14)

First and second polarizing layers each including a first region having an absorption axis formed in a first direction and a second region having an absorption axis formed in a second direction different from the first direction are disposed to face each other; And at least one of the first and second polarizing layers is a guest host type dye layer comprising a polymerizable liquid crystal compound and a dichroic dye. The optical element according to claim 1, wherein the first and second regions have stripe shapes extending in a common direction and are alternately arranged. The method of claim 1, wherein the first region of the first polarizing layer is disposed so as to face the first region of the second polarizing layer, and the first region of the first polarizing layer is formed of the second polarizing layer. And first and second polarizing layers arranged such that relative positions of the first and second polarizing layers can be changed so as to be moved to a second state facing the second region. The first region of the first polarization layer and the first region of the second polarization layer are arranged such that absorption axes are parallel to each other, and the second region of the first polarization layer and the second polarization layer are formed. The two regions are optical elements arranged such that the absorption axes are parallel to each other. The method of claim 3, wherein the absorption axes of the first region of the first polarization layer and the second region of the second polarization layer are disposed to be perpendicular to each other, and the first region of the second region and the second polarization layer of the first polarization layer. The absorption axis of the region is disposed so as to be perpendicular to each other. The optical element according to claim 1, wherein the first and second polarizing layers are guest host type dye layers each containing a polymerizable liquid crystal compound and a dichroic dye. The optical device of claim 1, wherein the dye layer is a coating layer of a polarizing material comprising a polymerizable liquid crystal compound and a dichroic dye. The optical device according to claim 1, wherein the polymerizable liquid crystal compound is contained in the first polarizing layer or the second polarizing layer in a horizontally circulated state. The optical device of claim 1, wherein the dichroic dye exhibits a maximum absorbance within the wavelength range of 400 nm to 700 nm. The optical element according to claim 1, wherein the dichroic ratio of the dichroic dye is 5 or more. The optical element according to claim 1, further comprising an alignment film formed on one surface of the first and second polarizing layers. The optical device according to claim 11, wherein the alignment film is a photoalignment film containing a photoalignment compound. The optical element according to claim 1, further comprising a base layer formed on one surface of the first and second polarizing layers. Smart blind comprising the optical element of claim 1.

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