KR102079136B1 - Transmission Controllable Device - Google Patents

Abstract

The present invention relates to a variable transmittance device. The variable transmittance device of the present invention uses at least one guest host liquid crystal cell and an optical member, and specifies the position of the spacer fixed to the substrate of the guest host liquid crystal cell, thereby minimizing transmittance and optimizing transmittance uniformity in the light shielding mode. can do.

Description

Transmission controllable device

The present invention relates to a variable transmittance device and its use.

The guest host liquid crystal cell may control absorption of a desired wavelength by adding a dichroic dye as a guest to a liquid crystal as a host. When the guest host liquid crystal cell is uniaxially oriented in parallel to the substrate, only the light in the uniaxial direction is absorbed by the dichroic dye and thus may play a role similar to that of the polarizer.

Republic of Korea Patent Publication No. 2017-0004909

When two guest host liquid crystal cells are superimposed and implemented as a double cell, or one guest host liquid crystal cell and one polarized device are implemented as a single cell, a low transmittance can be obtained due to the cross-pol. Can be used as a device. Meanwhile, in order to implement the guest host liquid crystal cell as a film cell, a spacer fixed to the substrate is required.

The inventors of the present invention have found that when the variable transmissivity device is implemented using a guest host liquid crystal cell, characteristics at low transmittance vary depending on the position of the spacer fixed to the substrate. An object of the present invention can be to provide a variable transmittance device and its use that can minimize the transmittance and optimize the uniformity in the light shielding mode, using a guest host liquid crystal cell.

The present invention relates to a variable transmittance device. As used herein, the term variable transmittance device may refer to a device designed to switch between a high transmittance state and a low transmittance state. As described below, in the structure including at least one guest-host liquid crystal layer, switching between the states can be enabled by controlling the orientation of the dichroic dye in the guest-host liquid crystal layer. .

As shown in FIG. 1, the variable transmittance device of the present application sequentially includes a first liquid crystal cell and a second liquid crystal cell including a first substrate 101, a first guest host liquid crystal layer 102, and a second substrate 103. It may include an optical member 20 disposed outside the substrate. The first liquid crystal cell may include a first spacer fixed to an inner surface of the first substrate and not fixed to an inner surface of the second substrate. The optical member may be a second liquid crystal cell or a polarizer that sequentially includes a third substrate, a second guest host liquid crystal layer, and a fourth substrate. As used herein, the term “inner” may mean a direction in which the guest host liquid crystal layer exists.

The variable transmittance device of the present application includes at least one guest host liquid crystal cell and an optical member, and when the fixed spacer is designed to be located on the inner surface of the substrate on the opposite side where the optical member of the guest host liquid crystal cell is present, Permeability can be minimized and permeability uniformity can be optimized.

The first liquid crystal cell and the optical member are included in the device in a state where they overlap each other. Accordingly, the light transmitted through the first liquid crystal cell may be incident to the second liquid crystal cell or the polarizer, and the light transmitted through the second liquid crystal cell or the polarizer may be incident to the first liquid crystal cell.

Hereinafter, the variable transmittance device of the present application will be described in detail.

2 exemplarily shows a variable transmittance device according to a first embodiment of the present application. According to the first embodiment of the present application, the optical member may be a second liquid crystal cell. The variable transmittance device is disposed outside the first liquid crystal cell and the second substrate sequentially including a first substrate 101, a first guest host liquid crystal layer 102, and a second substrate, and a third substrate 201. And a second liquid crystal cell sequentially including the second guest host liquid crystal layer 202 and the fourth substrate 204.

The first and second guest host liquid crystal layers may each include a liquid crystal and a dichroic dye. Hereinafter, while describing the liquid crystal and the dichroic dye, the content can be commonly applied to the liquid crystal and the dichroic dye of the first and second guest host liquid crystal layers unless otherwise specified.

As used herein, the term "guesthost liquid crystal layer" is a dichroic dye is arranged together in accordance with the arrangement of the liquid crystal, the functionality showing anisotropic light absorption characteristics, respectively, with respect to the alignment direction of the dichroic dye and the direction perpendicular to the alignment direction May mean a layer. For example, a dichroic dye is a substance whose light absorption rate varies depending on the polarization direction. If the absorption rate of light polarized in the long axis direction is large, it can be referred to as a p-type dye. It may be called dye. In one example, when a p-type dye is used, the polarized light vibrating in the long axis direction of the dye is absorbed and the polarized light vibrating in the short axis direction of the dye is less absorbed and thus can be transmitted. Unless otherwise specified, the dichroic dye is assumed to be a p-type dye.

The device including the guest host liquid crystal layer may function as an active polarizer. As used herein, the term "active polarizer" may refer to a functional device capable of adjusting anisotropic light absorption according to application of external action. For example, the guest host liquid crystal layer may control anisotropic light absorption for polarization in a direction parallel to the arrangement direction of the dichroic dye and polarization in a vertical direction by adjusting the arrangement of the liquid crystal and the dichroic dye. Since the arrangement of the liquid crystal and the dichroic dye can be controlled by the application of an external action such as a magnetic field or an electric field, the guest host liquid crystal layer can adjust the anisotropic light absorption according to the application of the external action.

As said liquid crystal, the liquid crystal which can switch an arrangement state according to voltage application can be selected suitably, and can be used. As said liquid crystal, a nematic liquid crystal can be used, for example. In the present specification, the nematic liquid crystal may refer to a liquid crystal in which rod-shaped liquid crystal molecules have no regularity of position but are arranged in parallel in the long axis direction of the liquid crystal molecules.

The dielectric anisotropy of the liquid crystal may be positive or negative. As used herein, the term "dielectric anisotropy (Δε)" may mean the difference (ε / /-ε ⊥) of the horizontal dielectric constant (ε / /) and the vertical dielectric constant (ε 의) of the liquid crystal. As used herein, the term "horizontal dielectric constant (ε //)" refers to a dielectric constant value measured along the direction of the electric field while a voltage is applied such that the direction of the electric field due to the director of the liquid crystal molecules and the applied voltage is substantially horizontal. In addition, the "vertical dielectric constant (ε⊥)" means a dielectric constant value measured along the direction of the electric field in the state where a voltage is applied so that the direction of the electric field by the director of the liquid crystal molecules and the applied voltage is substantially perpendicular. The value of the dielectric anisotropy of the liquid crystal may be appropriately selected in consideration of the purpose of the present application.

As used herein, the term "dye" may mean a material capable of intensively absorbing and / or modifying light in at least part or the entire range within the visible light region, for example, in the 400 nm to 700 nm wavelength range, The term "dichroic dye" may refer to a material capable of dichroic 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 have a property that can be aligned according to the alignment state of the liquid crystal can be selected and used. As a dichroic dye, black dye can be used, for example. Such dyes are known as, for example, azo dyes, anthraquinone dyes, and the like, but are not limited thereto.

The dichroic ratio of the dichroic dye may be appropriately selected in consideration of the purpose of the present application. For example, the dichroic dye may have a dichroic ratio of 5 to 20 or less. In the present specification, the term “dichroic ratio”, for example, in the case of a p-type dye, may mean a value obtained by dividing absorption of polarized light parallel to the long axis direction of the dye by absorption of polarized light parallel to the direction perpendicular to the long axis direction. Can be. The dichroic dye may have the dichroic ratio at at least some of the wavelengths or at any wavelength within the wavelength range of the visible light region, for example, in the wavelength range of about 380 nm to 700 nm or about 400 nm to 700 nm.

The content of the dichroic dyes of the first and second guest host liquid crystal layers may be appropriately selected in consideration of the purpose of the present application. For example, the dichroic dye content of the first and second guest host liquid crystal layers may be 0.1 wt% or more and 10 wt% or less.

The first substrate, the second substrate, and the third to fourth substrates may each include a base layer, an electrode layer, and an alignment layer that are sequentially disposed in an inner direction.

That is, the first substrate may include a first base layer, a first electrode layer, and a first alignment layer sequentially disposed in a side direction of the first guest host liquid crystal layer. The second substrate may include a second substrate layer, a second electrode layer, and a second alignment layer that are sequentially disposed in a side direction of the first guest host liquid crystal layer. The third substrate may include a third base layer, a third electrode layer, and a third alignment layer that are sequentially disposed in a side direction of the second guest host liquid crystal layer. The fourth substrate may include a fourth substrate layer, a fourth electrode layer, and a fourth alignment layer that are sequentially disposed in a side direction of the second guest host liquid crystal layer.

In one example, each of the second substrate layer and the third substrate layer may be a separate substrate layer. In this case, the second base layer and the third base layer may be attached via any pressure-sensitive adhesive layer. In another example, any one of the base layers may perform the functions of the second base layer and the third base layer. Hereinafter, the base layer, the electrode layer, and the alignment layer are described, unless otherwise specified. It is the content which can be commonly applied to the base material layer, the electrode layer, and the alignment film included in the first substrate, the second substrate, and the third to fourth substrates, respectively.

As the substrate layer, a known material may be used without particular limitation. For example, an inorganic substrate such as a glass substrate, a crystalline or amorphous silicon substrate, a quartz or an ITO (Indium Tin Oxide) substrate, a plastic substrate, or the like can be used.

As the plastic substrate, triacetyl cellulose (TAC); Cyclo olefin copolymer (COP) 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) or polyarylate (PAR) or amorphous fluorine resin The thickness of the base layer is not particularly limited and may be selected in an appropriate range.

In one example, an optically isotropic substrate or an optically anisotropic substrate layer may be used as the first and / or fourth substrate layers. As the second and / or third base layer, an optically isotropic substrate layer, for example, a PC (polycarbonate) film, a COP (cyclo olefin copolymer) film, or a PI (polyimide) film may be used.

The electrode layer may be present on the base layer. As the electrode layer, a transparent conductive layer may be used. The transparent conductive layer may be formed by depositing a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as indium tin oxide (ITO). In addition, various materials and forming methods capable of forming a transparent conductive layer are known and may be applied without limitation.

The alignment layer may be present on the electrode layer. As the alignment layer, a horizontal alignment layer or a vertical alignment layer may be used. In one example, all of the first, second, third and fourth alignment layers may be horizontal alignment layers or all vertical alignment layers. As the alignment layer, a contact alignment layer such as a rubbing alignment layer or a non-contact alignment layer such as a photo alignment layer may be used.

The first liquid crystal cell and the second liquid crystal cell may each include a spacer. The first liquid crystal cell may include a first spacer fixed to an inner surface of the first substrate. The second liquid crystal cell may include a second spacer fixed to an inner surface of the fourth substrate. In the present specification, the spacer is fixed to the substrate, which means that the spacer is simply in contact with the substrate, and may mean that the spacer is firmly attached to one surface of the substrate. Whether the spacer is fixed to the substrate can be confirmed, for example, on which substrate the spacer remains when the device is disassembled.

In one example, the first spacer may be fixed to the inner surface of the first alignment layer included in the first substrate. The first spacer may serve to maintain a gap between the first substrate and the second substrate.

In one example, the second spacer may be fixed to the inner surface of the fourth alignment layer included in the fourth substrate. The second spacer may serve to maintain a gap between the third substrate and the fourth substrate.

The first spacer may not be fixed to an inner surface of the second substrate. That is, the first spacer may not be fixed to the inner surface of the second alignment layer. The second spacer may not be fixed to an inner surface of the third substrate. That is, the second spacer may not be fixed to the inner surface of the third alignment layer. When the variable transmittance device is implemented by overlapping at least one guest host liquid crystal cell and the optical member as in the present application, a polarization component is determined in the second to third substrates where the guest host liquid crystal cell and the optical member meet, and the cross pole By the effect, low transmittance can be achieved. In the case of using the spacer fixed to the substrate in order to maintain the gap between the substrates, the area of the defective portion where the spacers are fixed is generated by the alignment film tail or the like. Therefore, when the fixation spacer is positioned on the surfaces of the second to third substrates where the guest host liquid crystal cell and the optical member meet, the polarization effect may be reduced by the misalignment region. For this reason, when the light blocking mode is to be implemented by the variable transmittance device, transmittance may increase and transmittance uniformity may decrease.

According to the present application, as described above, the fixation spacer is positioned on the surface of the substrate on the opposite side to the side where the optical member of the guest host liquid crystal cell exists, and is located on the surface of the substrate on the side where the optical member of the guest host liquid crystal cell exists. In order to implement the light blocking mode with the variable transmittance device, the transmittance may be minimized and the uniformity of transmittance may be optimized.

The first spacer and the second spacer may be fixed to the first to fourth substrates, respectively, by a known spacer fixing method. In one example, the first spacer and the second spacer may each be present in a state of being fixed to the inner surface of the first to fourth substrate via the cured product. Specifically, the first spacer may be adhered to one surface of the first substrate by coating, drying, and curing the composition including the first spacer, the curable material, and the solvent on the first substrate. In addition, the second spacer may be adhered to one surface of the fourth substrate by coating, drying, and curing the composition including the second spacer, the curable material, and the solvent on the fourth substrate.

The cured product may include a curable material. As the curable material, a thermosetting material or a photocurable material may be used. As the photocurable material, an ultraviolet curable material may be used. As said thermosetting material, a silicone resin, a silicon resin, a frans resin, a polyurethane resin, an epoxy resin, an amino resin, a phenol resin, a urea resin, a polyester resin, a melamine resin, etc. can be used, for example. Such ultraviolet curable materials are typically acrylic polymers such as polyester acrylate polymers, polystyrene acrylate polymers, epoxy acrylate polymers, polyurethane acrylate polymers or polybutadiene acrylate polymers, silicone acrylate polymers or alkyl acrylics. Late polymer and the like can be used.

As the curable material, an orientation material may be used. As the oriented material, polyamide, polyimide, polyvinyl alcohol, polyamic acid or poly cinnamate may be used.

The shape of the first and second spacers may be appropriately selected in consideration of the purpose of the present application. Ball spacers or column spacers may be used as the first and second spacers, respectively. The size of the first and second spacers may be appropriately selected in consideration of the gap between the first substrate and the second substrate and the gap between the third substrate and the fourth substrate. The spacer may include one or more selected from the group consisting of carbon-based materials, metal-based materials, oxide-based materials, and composite materials thereof.

According to the second embodiment of the present application, the optical member may be a polarizing element. The variable transmittance device may include a first liquid crystal cell sequentially including a first substrate, a first guest host liquid crystal layer, and a second substrate, and a polarizer disposed outside the second substrate.

In the variable transmittance device of the second embodiment, the contents of the first liquid crystal cell may be equally applied to the contents of the variable transmittance device of the first embodiment unless otherwise specified.

The polarizer may not be a liquid crystal cell. The polarizer may be a linear polarizer. In the present specification, the linearly polarized light refers to a case in which the light selectively transmitting is linearly polarized in one direction and the light selectively absorbed or reflected is linearly polarized in the direction orthogonal to the vibration direction of the linearly polarized light. That is, the linear polarizer may have a transmission axis orthogonal to the plane direction and an absorption axis or a reflection axis.

The polarizer may be an absorbing polarizer or a reflective polarizer. As the absorption type polarizer, for example, a polymer polarized film, such as a PVA stretched film or the like, is used as a polarizer or a liquid crystal polymerized in an oriented state as a host, and anisotropic dyes arranged according to the alignment of the liquid crystal are used as a host. A guest-host polarizer may be used, but is not limited thereto. As the reflective polarizer, for example, a reflective polarizer known as a dual brightness enhancement film (DBEF) or a reflective polarizer formed by coating a liquid crystal compound such as LLC (Lyotropic liquid crystal) may be used. It is not limited to this.

The variable transmittance device of the present application can adjust the transmittance by adjusting the alignment direction of the liquid crystal and the dichroic dye depending on whether a voltage is applied to at least one guest host liquid crystal cell. The alignment direction may be adjusted by adjusting the pretilt angle and the pretilt direction of the alignment layer included in the guest host liquid crystal cell. In one example, the variable transmittance device may switch the transparent mode and the light blocking mode according to whether or not a voltage is applied to at least one guest host liquid crystal cell. The transparent mode may mean a state showing a relatively high transmittance, and the light blocking mode may mean a state showing a relatively low transmittance. In one example, at least one guest host liquid crystal cell in the variable transmittance device may exist in a vertical alignment state or a horizontal alignment state when no voltage is applied, and may be switched to a horizontal alignment state or a vertical alignment state when voltage is applied.

In the present specification, the vertical alignment state is a state in which the directors of the liquid crystal molecules are vertically arranged with respect to the plane of the liquid crystal layer, for example, an arrangement state in which a pretilt angle of 60 degrees to 90 degrees, and preferably about 80 degrees to 90 degrees is achieved. It may mean.

In the present specification, the horizontal alignment state is a state in which the directors of the liquid crystal molecules are arranged in parallel with respect to the plane of the liquid crystal layer, for example, an arrangement state in which a pretilt angle of 0 degrees to 30 degrees, preferably 0 degrees to 10 degrees is formed. Can mean.

The arrangement state of the first and second guest host liquid crystal layers is not limited to the vertical alignment state and the horizontal alignment state, and the intermediate state between the transparent mode and the light blocking mode is adjusted by adjusting the pretilt angle to an angle between the vertical alignment and the horizontal alignment. The transmittance of the state may also be shown.

According to the transmittance variable device of the first embodiment, the optical member is a second liquid crystal cell, and the transparent mode and the light blocking mode may be switched depending on whether voltage is applied to the first and second guest host liquid crystal layers, respectively. The first and second guest host liquid crystal layers may exist in a vertical alignment state or a horizontal alignment state, respectively, when no voltage is applied.

In the transparent mode, the first guest host liquid crystal layer and the second guest host liquid crystal layer may each exist in a vertical alignment state. In the light blocking mode, the first guest host liquid crystal layer and the second guest host liquid crystal layer may exist in a horizontal alignment state where the alignment directions are perpendicular to each other.

Hereinafter, the principle of adjusting the transmittance of the variable transmittance device of the first embodiment of the present application will be described in detail. When the first and second guest host liquid crystal layers exist in a vertical alignment state in the variable transmittance device of the present application, the transparent mode may be implemented through the transmission in the uniaxial direction of the dichroic dye. In one example, the variable transmittance device may exhibit a transmittance of about 50% or more in the transparent mode. In the variable transmittance device of the present application, when the first and second guest host liquid crystal layers exist in a horizontal alignment state where the alignment directions are perpendicular to each other, the absorption axis of the first guest host liquid crystal layer and the absorption axis of the second guest host liquid crystal layer Since this orthogonality can be achieved, the light-shielding mode can be realized by lowering the transmittance by the cross pole effect. In one example, the variable transmittance device may exhibit a transmittance of about 10% or less in the light blocking mode.

The variable transmittance device of the present application may control whether to implement a transmission mode or a light shielding mode when a voltage is applied through selection of a type of liquid crystal and an alignment layer. In one example, when a liquid crystal having negative dielectric anisotropy is used and a vertical alignment layer is used as the first, second, third and fourth alignment layers, a transparent mode may be realized through a vertical alignment state when no voltage is applied. When the voltage is applied, the light blocking mode may be realized through the horizontal alignment state. In another example, when a liquid crystal having positive dielectric anisotropy is used and a horizontal alignment layer is used as the first, second, third and fourth alignment layers, a light blocking mode may be realized through a horizontal alignment state when no voltage is applied. The transparent mode may be realized through a vertical alignment state when a voltage is applied.

According to the transmittance variable device of the second embodiment, the optical member is a polarizing element, and the transparent mode and the light blocking mode may be switched depending on whether a voltage is applied to the first guest host liquid crystal layer. The first guest host liquid crystal layer may exist in a vertical alignment state or a horizontal alignment state when no voltage is applied.

In the transparent mode, the first guest host layer may exist in a vertical alignment state. In the light blocking mode, the alignment direction of the first guest host liquid crystal layer may exist in a horizontal alignment state to be parallel to the transmission axis of the polarizer.

Hereinafter, the principle of adjusting the transmittance of the variable transmittance device of the second embodiment of the present application will be described in detail. When the first guest host liquid crystal layer is present in the vertical alignment state in the variable transmittance device of the present application, the transparent mode may be implemented through transmission in the uniaxial direction of the dichroic dye. When the orientation direction of the first guest host liquid crystal layer is present in the horizontal alignment state in parallel with the transmission axis of the polarizing element in the variable transmittance device of the present application, the absorption axis of the first guest host liquid crystal layer and the absorption axis of the polarizing element to Since the reflection axis may be orthogonal, the light blocking mode may be realized by reducing the transmittance due to the cross pole effect.

Such a variable transmittance device can be applied to various applications. Examples of applications to which the variable transmittance device may be applied include openings, eyewear, and the like in enclosed spaces including buildings, containers, vehicles, etc., such as windows or sunroofs. The eyewear may include all eyewear configured to allow the observer to observe the outside through a lens, such as general glasses, sunglasses, sports goggles or a helmet, or an augmented reality experience device.

Eyewear is a representative application to which the variable transmittance device of the present application may be applied. Recently, sunglasses, sports goggles and augmented reality experience devices, such as eyewear in the form of a lens is mounted on the market so as to be inclined with the observer's frontal view. In the case of the variable transmittance device of the present application, as described above, it is possible to minimize the transmittance in the light-shielding mode and ensure the uniformity of the transmission, it can be effectively applied to the eyewear having the above structure. As such eyewear, sports goggles or augmented reality experience devices may be exemplified.

The variable transmittance device of the present invention uses a guest host double cell, and specifies the location of the spacer fixed to the substrate to minimize the transmittance and optimize the uniformity of the transmittance in the light shielding mode.

1 and 2 are schematic diagrams of a variable transmittance device of the present application.
3 is a transmission uniformity observation image of Example 1, Comparative Example 1 and Comparative Example 2.
4 is a transmission uniformity observation image of Example 2 and Comparative Example 3.
5 is a transmission uniformity observation image of Example 2 and Comparative Example 3.

Hereinafter, the present application will be described in detail with reference to Examples, but the scope of the present application is not limited by the following Examples.

Example  One

The substrate having the spacers fixed by mixing the vertical alignment layer and the solvent mixture (solid content 1wt%) with a spacer having a size of 12 μm (compared to the total solution) of 12 μm, followed by coating on a PC-ITO film and drying at 130 ° C. for 10 minutes. Was prepared. A substrate in which no spacer was fixed was manufactured in the same manner as the substrate except that no spacer was included. After rubbing the alignment layer coating surfaces of the two substrates, a mixture of the liquid crystal and the dye was placed therebetween, and the cells were bonded to prepare a first liquid crystal cell. A second liquid crystal cell was manufactured in the same manner as the first liquid crystal cell. At this time, the first liquid crystal cell and the second liquid crystal cell were bonded together using an OCA so that the substrates to which the spacers were not fixed were bonded to each other to manufacture a variable transmittance variable device. Hereinafter, the outer substrates of the first liquid crystal cell and the second liquid crystal cell are referred to as the first substrate and the fourth substrate, respectively, and the inner substrates of the first liquid crystal cell and the second liquid crystal cell are referred to as the second substrate and the third substrate, respectively. do.

3A is an image of the uniformity of the transmission of Example 1 observed with a microscope and the naked eye.

Example  2

The liquid crystal cell was manufactured by the same method as the 1st liquid crystal cell of Example 1. An absorption type polarizing plate (PVA-based polarizing plate) was laminated on a substrate on which a spacer was not fixed so that its transmission axis coincided with the rubbing axis of the liquid crystal cell, thereby manufacturing a variable transmittance device of Example 2.

4A is an image of the transmission uniformity of Example 2 observed with a microscope.

Example  3

A variable transmittance device was manufactured in the same manner as in Example 2, except that the absorption type polarizing plate was changed to a reflective polarizing plate (DBEF film).

FIG. 5A is an image of the transmission uniformity of Example 3 observed with a microscope. FIG.

Comparative example  One

A variable transmittance device was manufactured in the same manner as in Example 1, except that the fixed spacer was changed to be positioned on the first and third substrates.

3B is an image in which the transmission uniformity of Comparative Example 1 was observed with a microscope and the naked eye.

Comparative example  2

A variable transmittance device was manufactured in the same manner as in Example 1, except that the fixed spacer was changed to be positioned on the second and third substrates.

3C is an image in which the transmission uniformity of Comparative Example 2 was observed with a microscope and the naked eye.

Comparative example  3

In Example 2, a variable transmittance device was manufactured in the same manner as in Example 2, except that the absorbing polarizing plate was laminated on the substrate to which the spacer was fixed.

4B is an image of the transmission uniformity of Comparative Example 3 observed with a microscope.

Comparative example  4

In Example 3, a variable transmittance device was manufactured in the same manner as in Example 3, except that the reflective polarizing plate was laminated on the substrate to which the spacer was fixed.

5B is an image of the transmission uniformity of Comparative Example 3 observed with a microscope.

Experimental Example  One

For Example 1 and Comparative Examples 1 to 2 using a hazemeter (Hazemeter, NDH-5000SP) equipment was measured the transmittance according to whether the voltage is applied and the results are shown in Table 1 below.

0V transmittance (%) 10V transmittance (%) Example 1 51.7 5.9 Example 2 28.8 3.3 Example 3 36.4 5.5 Comparative Example 1 51.4 6.3 Comparative Example 2 51.8 7.0 Comparative Example 3 28.1 4.5 Comparative Example 4 36.2 6.1

101: first substrate, 102: first guest host liquid crystal layer, 103: second substrate, 20: optical member, 201: third substrate, 202: second guest host liquid crystal layer, 203: fourth substrate

Claims (15)

A first liquid crystal cell including a first substrate, a first guest host liquid crystal layer, and a second substrate in order, and disposed outside the second substrate, and sequentially forming a third substrate, a second guest host liquid crystal layer, and a fourth substrate; And a second liquid crystal cell, wherein the first liquid crystal cell is fixed to an inner surface of the first substrate, and includes a first spacer which is not fixed to an inner surface of the second substrate. And the cell is secured to the inner surface of the fourth substrate, and the second spacer is not secured to the inner surface of the third substrate. The device of claim 1, wherein the first and second guest host liquid crystal layers each include a liquid crystal and a dichroic dye. The device of claim 1, wherein the first spacer is fixed to the inner surface of the first substrate by a cured product, and maintains a gap between the first substrate and the second substrate. delete The apparatus of claim 1, wherein the second spacer is fixed to the inner surface of the fourth substrate by a cured product, and maintains a gap between the third substrate and the fourth substrate. The apparatus of claim 1, wherein the first to fourth substrates each include a base layer, an electrode layer, and an alignment layer that are sequentially disposed in an inward direction. The device of claim 1, wherein the transparent mode and the light blocking mode are switched according to whether voltage is applied to the first and second guest host liquid crystal layers, respectively. 8. The variable transmittance device of claim 7, wherein the first or second guest host liquid crystal layer is in a vertical alignment state or a horizontal alignment state, respectively, when no voltage is applied. The apparatus of claim 7, wherein the first guest host liquid crystal layer and the second guest host liquid crystal layer are each in a vertical alignment state in the transparent mode. The apparatus of claim 7, wherein in the light blocking mode, the first guest host liquid crystal layer and the second guest host liquid crystal layer are in a horizontal alignment state in which the alignment directions are perpendicular to each other. delete delete delete delete delete

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