KR102071908B1 - Optical device with improved heat durability - Google Patents

Abstract

The present application relates to an optical element and its use, the optical element of the present application is a member whose transmittance can be varied depending on the presence of external action, has a structure that has improved stability from thermal stress, thereby excellent durability Do.

Description

Optical device with improved heat durability

The present application is directed to optical devices and their use.

A sunroof typically refers to a fixed or actuating (venting or sliding) opening that is present on the ceiling of a vehicle and serves to allow light or fresh air to enter the interior of the vehicle. The sunroof can be operated manually or driven by a motor, and there are various types of sunroof depending on the intended use. For example, the sunroof is a pop-up type sunroof, a spoiler (tile & slide) type sunroof, an inbuilt type sunroof, a folding type sunroof, a top-mounted type sunroof, a panoramic loop. System type sunroof, t-tops or targa roofts type sunroof or solar type sunroof. Moreover, research on the material of a sunroof is also actively progressing, for example, patent document 1 is disclosing the technique of manufacturing the sunroof excellent in the absorption of an ultraviolet-ray and a solar ray using the glass composition of a specific composition.

Generally, the optical element used as the sunroof film includes a glass layer, a polarizing layer, a first substrate, a second substrate, and the like, and in order to satisfy the optical characteristics of the optical element, the glass layer, the polarizing layer, the first substrate, and the first The two substrates must use different materials. In this case, each layer has a difference in coefficient of thermal expansion (CTE), causing thermal stress at high temperatures. This thermal stress has a problem of causing a breakage of the substrate.

Therefore, even when a substrate having a different thermal expansion coefficient is used, there is a need for the development of an optical device that is free from thermal stress and thus has improved thermal structural stability.

International Application Publication No. 2010-098576.

The present application provides an optical device whose transmittance is changed depending on whether an external action is applied.

The optical element of the said application can prevent the durability fall by thermal deformation effectively.

The present application is directed to optical devices and their use.

In the optical element of the present application, the transmittance is changed depending on whether an external action is applied, and the optical element may be used in a variable transmittance member, for example, a sunroof for a vehicle.

The optical element according to the present application furthermore, by appropriately designing the position and structure of the substrate layer, the polarizing layer and the substrates, the deformation of the device according to the difference in the elastic modulus and thermal expansion coefficient between the substrate and the polarizing layer or between the substrate and other layers Can be effectively prevented.

Such, the optical device of the present application is a base layer; A polarizing layer positioned on the base layer; A first substrate positioned on the polarizing layer; A second substrate positioned on the first substrate; And a liquid crystal layer positioned between the first substrate and the second substrate, wherein at least one of the base layer, the polarizing layer, and the second substrate has a larger area than the first substrate, and between the polarizing layer and the second substrate. It further comprises a first sealant located on both sides.

That is, the optical element of the present application, the area of each of the polarizing layer and the second substrate has a larger area than the first substrate, and further includes a first sealant located on both sides between the polarizing layer and the second substrate 1 The stress that may occur due to the difference in thermal expansion coefficient between the substrate and the second substrate may be minimized, and ultimately, deformation due to shrinkage or expansion of the device and thus change of optical properties may be prevented.

In one example, the area of the polarizing layer may be 1.1 to 5 times, 1.2 times to 4.5 times, 1.3 times to 4 times, 1.4 times to 3.5 times, or 1.5 times to 3 times the first substrate area, but is not limited thereto. It is not. The area of the second substrate may also be 1.1 times to 5 times, 1.2 times to 4.5 times, 1.3 times to 4 times, 1.4 times to 3.5 times, or 1.5 times to 3 times the first substrate area, but is not limited thereto. The area of the polarizing layer and the area of the second substrate may be equally formed.

In addition, the area of the base layer and the area of the polarizing layer may be formed to be the same.

In one example, the optical device of the present application may have a strain (%) of 1% or less after a 240 hours heat test at a temperature of 120 ° C.

The strain (%) may be calculated by, for example, Equation 1 below.

[Equation 1]

Strain (%) = | (L2-L1) | / L1 x 100

In Equation 1, L1 is the initial length of the device specimen, L2 is the later length of the device specimen after standing for 240 hours at 120 ℃.

Since the small percentage (%) means that the shrinkage or expansion of the optical element is small, the value is not particularly limited within the range of 1% or less, for example, 0.8% or less, 0.5% or less, or 0. Can be%.

In the present application, the base layer may be, for example, a transparent base film having a haze of 5% or less, or 3% or less.

The base layer may also have a refractive index of 550 nm between 1.5 and 2.0, or between 1.5 and 1.7.

The thickness of the substrate layer may be, for example, 30 to 300 µm, preferably 40 to 250 µm.

The glass transition temperature of the substrate layer may be, for example, in the range of 100 ° C to 300 ° C, preferably 100 ° C to 150 ° C.

The material of the base material layer is not limited as long as the above conditions are satisfied. For example, polyolefin such as polyethylene or polypropylene; Polyesters such as polyethylene terephthalate and polyethylene naphthalate; Celluloses such as triacetyl cellulose, diacetyl cellulose, propionyl cellulose, butyl cellulose or acetyl cellulose; Polyamides such as 6-nylon or 6,6-nylon; Acrylic polymers such as polymethyl methacrylate; It may be a polymer film formed of an organic polymer such as polystyrene, polyvinyl chloride, polyimide, polyvinyl alcohol, polycarbonate, or ethylene vinyl alcohol, or may be a glass substrate.

The base layer may be formed of one or two or more kinds of mixtures or polymers, or may have a structure in which a plurality of layers are laminated.

The substrate layer may have a modified surface. The surface modification is carried out for the purpose of securing adhesion to the electrode layer and the like, and a treatment method such as chemical treatment, corona discharge treatment, mechanical treatment, ultraviolet (UV) treatment, active plasma treatment or glow discharge treatment may be adopted. May be, but is not limited thereto.

The substrate layer as described above may, for example, blend the above-mentioned material with a known mixer (ex. Omni mixer, etc.), and the obtained mixture may be an extruder or pressurized kneader (ex. And the like, and then, may be manufactured by a known film forming method (eg, a solution casting method, a melt extrusion method, a calender method, a compression molding method, etc.), and particularly, by a solution casting method or a melt extrusion method. desirable.

In the present application, the first substrate serves as a supporter of the device, and may be used in the present application without limitation, as long as it is a material having proper rigidity, low warpage, and suitable transparency.

In one example, the first substrate comprises a glass substrate; Crystalline or amorphous silicon films; Inorganic films such as quartz or ITO films; Or a plastic substrate.

In a specific example, the plastic substrate may include 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 Polyphenylsulfone (PPS), polyetherimide (PEI); polyethylenemaphthatlate (PEN); polyethyleneterephtalate (PET); polyimide (PI); polysulfone (PSF); polyarylate (PAR) or amorphous fluorine resin It doesn't happen.

In the present application, the first substrate serves as a supporter of the device, and may be used in the present application without limitation, as long as it is a material having proper rigidity, low warpage, and suitable transparency.

In one example, the second substrate is a glass substrate; Crystalline or amorphous silicon films; Inorganic films such as quartz or ITO films; Or a plastic substrate.

In a specific example, the plastic substrate may include 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 Polyphenylsulfone (PPS), polyetherimide (PEI); polyethylenemaphthatlate (PEN); polyethyleneterephtalate (PET); polyimide (PI); polysulfone (PSF); polyarylate (PAR) or amorphous fluorine resin It doesn't happen.

The first substrate and the second substrate may be the same kind of substrates, or may be different kinds of substrates.

As used herein, the term polarizing layer may refer to a functional layer that exhibits selective transmission and blocking properties, for example, reflection or absorption properties, for incident light. For example, the polarizing layer may have a function of transmitting light oscillating in one direction from incident light oscillating in various directions and blocking light oscillating in the other direction.

The kind of the polarizing layer is not particularly limited, and a reflective type, an absorbing type, or a scattering type polarizing layer may be exemplified.

As the reflective polarizing layer, for example, a dual brightness enhancement film (DBEF), a lyotropic liquid crystal (LLC layer), a wire grid polarizer, or the like can be used. For example, a guest-host type polarizing layer comprising a polarizer in which iodine is salted in a polymer stretched film such as a PVA stretched film or a liquid crystal polymerized in an oriented state as a host, and an anisotropic dye arranged according to the alignment of the liquid crystal as a guest. May be used, but is not limited thereto.

The first substrate has, for example, a coefficient of thermal expansion (CTE) of less than 150 ppm / K, 90 ppm / K or less, 80 ppm / K or less, 70 ppm / K or less, 60 ppm / K or less, 50 ppm / K Up to 40 ppm / K, up to 30 ppm / K, or up to 20 ppm / K. Appropriate rigidity can be maintained within the range of the thermal expansion coefficient (CTE), and thermal deformation due to the laminated structure of the optical element can be prevented. The lower limit of the coefficient of thermal expansion (CTE) may be, for example, 3 ppm / K or more, 5 ppm / K or more, or 7 ppm / K or more, but is not limited thereto. The heat retention coefficient (CTE) value may be, for example, a value obtained by calculating an average thermal expansion coefficient as a linear thermal expansion coefficient measured while cooling and heating at a rate of 10 ° C./min in a temperature range of 0 ° C. to 100 ° C.

In the present application, the substrate layer may have a predetermined coefficient of thermal expansion (CTE).

In one example, the substrate layer has a coefficient of thermal expansion (CTE) of less than 150 ppm / K, 90 ppm / K or less, 80 ppm / K or less, 70 ppm / K or less, 60 ppm / K or less, 50 ppm / K or less , Up to 40 ppm / K, up to 30 ppm / K or up to 20 ppm / K. Appropriate rigidity can be maintained within the range of the thermal expansion coefficient (CTE), and thermal deformation due to the laminated structure of the optical element can be prevented. The lower limit of the coefficient of thermal expansion (CTE) may be, for example, 3 ppm / K or more, 5 ppm / K or more, or 7 ppm / K or more, but is not limited thereto. The heat retention coefficient (CTE) value may be, for example, a value obtained by calculating an average thermal expansion coefficient as a linear thermal expansion coefficient measured while cooling and heating at a rate of 10 ° C./min in a temperature range of 0 ° C. to 100 ° C.

In the present application, the second substrate may have a predetermined coefficient of thermal expansion (CTE).

In one example, the second substrate has a coefficient of thermal expansion (CTE) of less than 150 ppm / K, 90 ppm / K or less, 80 ppm / K or less, 70 ppm / K or less, 60 ppm / K or less, 50 ppm / K Up to 40 ppm / K, up to 30 ppm / K, or up to 20 ppm / K. Appropriate rigidity can be maintained within the range of the thermal expansion coefficient (CTE), and thermal deformation due to the laminated structure of the optical element can be prevented. The lower limit of the coefficient of thermal expansion (CTE) may be, for example, 3 ppm / K or more, 5 ppm / K or more, or 7 ppm / K or more, but is not limited thereto. The heat retention coefficient (CTE) value may be, for example, a value obtained by calculating an average thermal expansion coefficient as a linear thermal expansion coefficient measured while cooling and heating at a rate of 10 ° C./min in a temperature range of 0 ° C. to 100 ° C.

In the present application, the polarizing layer may directly contact the substrate layer, or may be attached to the substrate layer through an adhesive layer or an adhesive layer. At this time, the pressure-sensitive adhesive layer or the adhesive layer disposed between the polarizing layer and the base layer is, for example, acrylic; Epoxy-based; Urethane-based; Or rubber based; Known pressure-sensitive adhesives or adhesives such as pressure-sensitive adhesives or adhesives can be used without limitation. Specifically, the pressure-sensitive adhesive layer or the adhesive layer may be any one of a transparent adhesive film (OCA, Optically Clear Adhesive) and a pressure-sensitive silicone adhesive film PSA (Pressure Sensitive Adhesive), more specifically a pressure-sensitive silicone adhesive film (PSA, Pressure Sensitive Adhesive) can be used.

In addition, the first substrate may be in direct contact with the polarizing layer, or may be attached to the polarizing layer via an adhesive layer or an adhesive layer. At this time, the pressure-sensitive adhesive layer or the adhesive layer disposed between the first substrate and the polarizing layer is, for example, acrylic; Epoxy-based; Urethane-based; Or rubber based; Known pressure-sensitive adhesives or adhesives such as pressure-sensitive adhesives or adhesives can be used without limitation. Specifically, the pressure-sensitive adhesive layer or the adhesive layer may be any one of a transparent adhesive film (OCA, Optically Clear Adhesive) and a pressure-sensitive silicone adhesive film PSA (Pressure Sensitive Adhesive), more specifically a pressure-sensitive silicone adhesive film (PSA, Pressure Sensitive Adhesive) can be used.

The optical element of the present application further includes a second sealant positioned on at least one of both sides between the first substrate and the second substrate, both sides between the first substrate and the polarizing plate, and both sides between the first substrate and the base layer. can do. As an example, a sealant is positioned between the first substrate and the second substrate, that is, at the side of the liquid crystal layer, as shown in FIG. 1, to seal the liquid crystal compound in the liquid crystal layer while maintaining a gap between the liquid crystal layers. sealing can be performed.

In one example, the second substrate and the polarizing layer may have a larger area than the first substrate, and may further include a first sealant located at both sides between the polarizing layer and the second substrate. Specifically, the area of the second substrate is wider than that of the first substrate, thereby preventing the compression or expansion force of the second substrate from being transmitted to the first substrate, thereby effectively preventing damage and deformation of the first substrate.

The optical device according to the present application may prevent thermal stress from being transferred from the second substrate to the first substrate by including the first sealant between the second substrate and the polarizing layer, and thus thermal structural stability and durability of the optical device. Can improve.

1 exemplarily illustrates an optical device according to an embodiment of the present application. As shown in FIG. 1, the optical element includes a base layer 11, a polarization layer 30 positioned on the base layer, a first substrate 41 positioned on the polarization layer, and a first substrate positioned on the first substrate. And a second substrate 42, and an adhesive layer or an adhesive layer 21, 22 exists between the base layer 11, the polarizing layer 30, and the first substrate 41, respectively. The second sealant 52 is positioned on both sides between the first substrate 41 and the second substrate 42, and the liquid crystal layer 60 is present between the first substrate 41 and the second substrate 42, and the second substrate Each of the 42, the polarizing layer 30, and the base layer 11 is formed to have a larger area than that of the first substrate 42, so that the first substrate is disposed on both sides between the second substrate 42 and the polarizing layer 30. Sealant 51 may be located. The optical element of the present application has the above structure, it is possible to prevent the phenomenon that the thermal stress caused by the difference in the coefficient of thermal expansion of the first substrate and the second substrate. Accordingly, the thermal structural stability and durability of the optical element can be improved.

In one example, the sealant may be a polymer layer. Such a polymer layer may be, for example, of a type capable of thermal curing, UV curing or both thermal curing and UV curing.

In the present application, the sealant may mean any one or more of the first sealant and the second sealant, and the first sealant and the second sealant may be the same or different. In addition, the first sealant and the second sealant may have different elastic modulus values.

In one example, the sealant may be an acrylic polymer layer comprising polymerized units of (meth) acrylic acid esters.

The (meth) acrylic acid ester refers to methacrylic acid or acrylic acid or a derivative thereof, and specific (meth) acrylic acid ester may be an alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms, and Examples are methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate , sec-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylic Acrylate, n-octyl (meth) acrylate, disil (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, octadecyl (meth) acrylate, isooctyl (meth) acrylate Agent, isononyl (meth) acrylate or the like, but tetradecyl (meth) acrylate can be exemplified, without being limited thereto.

In addition, the acrylic polymer layer may further include polymerized units of monomers having other crosslinkable functional groups. The monomer having the crosslinkable functional group is, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl Hydroxyalkyl (meth) acrylates such as (meth) acrylate or 8-hydroxyoctyl (meth) acrylate, 2-hydroxypolyethylene glycol (meth) acrylate or 2-hydroxypolypropylene glycol (meth) acrylic Monomers having a hydroxyl group such as a rate; Or (meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy butyl acid, acrylic acid duplex, itaconic acid, maleic acid Or a monomer having a carboxyl group such as maleic anhydride and the like can be exemplified, but is not limited thereto.

The thickness of the sealant may be, for example, in the range of 5 to 100 μm, and may provide structural stability to the liquid crystal layer within this range.

In one example, the sealant may have a width of 3 mm to 15 mm, but is not limited thereto.

The sealant may have, for example, an area of 30% or less, 20% or less, 10% or less or 1% or less of the area of the liquid crystal layer. The said area means the ratio of the surface which the sealant contact | connects a liquid crystal layer. Within this area range, it may serve to maintain the gap between the liquid crystal layer and to seal the liquid crystal layer, and may not impair the variable transmittance of the liquid crystal compound in the liquid crystal layer.

The sealant (Sealant), in addition to the polymer described above may further include a suitable additive, in order to adjust the permeability variable properties, or rigidity. For example, the sealant may further contain an appropriate amount of known inorganic particles, inorganic pigments, and the like in order to adjust the permeability variable characteristics, rigidity, and the like.

In the present application, the first sealant may have, for example, an elastic modulus of 20 GPa or less, 15 GPa or less, or 10 GPa or less. Appropriate rigidity can be maintained within the range of such elastic modulus, and thermal deformation due to the laminated structure of the optical element can be prevented. The lower limit of the elastic modulus may be, for example, 0.5 GPa or more or 2.5 GPa or more, but is not limited thereto. The elastic modulus value may mean a value measured according to ASTM D882.

In addition, the second sealant may have a predetermined elastic modulus and thermal expansion coefficient (CTE).

In one example, the second sealant may have an elastic modulus of 20 GPa or less, 15 GPa or less, or 10 GPa or less. Appropriate rigidity can be maintained within the range of such elastic modulus, and thermal deformation due to the laminated structure of the optical element can be prevented. The lower limit of the elastic modulus may be, for example, 0.5 GPa or more or 2.5 GPa or more, but is not limited thereto. The elastic modulus value may mean a value measured according to ASTM D882.

The optical device of the present application may further include a barrier layer between the polarizing layer and the first substrate.

In one example, the barrier layer may be in direct contact with the polarizing layer and the first substrate, or may be attached to the polarizing layer and the first substrate via an adhesive layer or an adhesive layer. At this time, the pressure-sensitive adhesive layer or the adhesive layer disposed between the polarizing layer and the barrier layer or between the barrier layer and the first substrate is, for example, acrylic; Epoxy-based; Urethane-based; Or rubber based; Known pressure-sensitive adhesives or adhesives such as pressure-sensitive adhesives or adhesives can be used without limitation. Specifically, the pressure-sensitive adhesive layer or the adhesive layer may be any one of a transparent adhesive film (OCA, Optically Clear Adhesive) and a pressure-sensitive silicone adhesive film PSA (Pressure Sensitive Adhesive), more specifically a pressure-sensitive silicone adhesive film (PSA, Pressure Sensitive Adhesive) can be used.

The barrier layer may be, for example, a solid material, or a cured liquid, gel, or polymer, and may be selected from flexible or inflexible materials, depending on the application.

As one example, the metal applied to the barrier layer, specifically, the metal constituting the metal thin film layer or the deposition layer is, for example, aluminum (Al), copper (Cu), nickel (Ni), tin (Sn), zinc. (Zn), at least one selected from the group consisting of indium (In), silver (Ag), tungsten (W), iron (Fe), and the like (single metal or a mixture of single metals), or two or more alloys selected from them ( alloy) and the like, but are not limited thereto. For the metal oxide that can be used as the deposition layer, for example, aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ) and zinc oxide ( ZnO) and the like.

In addition, the barrier layer may include a resin layer, and the resin layer may be formed by applying a resin composition (adhesive composition) such as thermosetting type and photosetting type.

The kind of material for forming the barrier layer is not particularly limited and may be selected from known materials including glass, polymers, oxides or nitrides and the like. The barrier layer is, for example, glass; Polymers such as PET (poly (ethylene terephtalate)) and the like; Or an oxide or nitride such as silicon, titanium or aluminum, or a combination of two or more of the above, but is not limited thereto.

The barrier layer may be advantageous for improving the stability of the wavelength converting particles and protecting the wavelength converting particles from harmful external conditions including high temperature, high intensity, external gas or moisture, and the like. It can play a role.

2 exemplarily shows an optical device according to an embodiment of the present application. As shown in FIG. 2, the optical device includes a base layer 11, a polarization layer 30 disposed on the base layer, a barrier layer 70 positioned on the polarization layer 30, and a barrier layer 70 positioned on the barrier layer. A second sealant 52 on both sides between the first substrate 41 and the second substrate 42, the first substrate 41 and a second substrate 42 positioned on the first substrate 41. ) Is positioned, and the liquid crystal layer 60 may exist between the first substrate 41 and the second substrate 42. In this case, each of the adhesive layers or the adhesive layers 21, 22, and 23 may exist between the base layer 11, the polarizing layer 30, the barrier layer 70, and the first substrate 41. The optical element of the present application has the above structure, it is possible to prevent the phenomenon that the thermal stress caused by the difference in the coefficient of thermal expansion between each substrate. Accordingly, the thermal structural stability and durability of the optical element can be improved.

The optical device of the present application may further include a third substrate between the polarizing layer and the first substrate.

In one example, the third substrate may be in direct contact with the polarizing layer and the first substrate, or may be attached to the polarizing layer and the first substrate via an adhesive layer or an adhesive layer. At this time, the pressure-sensitive adhesive layer or the adhesive layer disposed between the polarizing layer and the third substrate or between the third substrate and the first substrate is, for example, acrylic; Epoxy-based; Urethane-based; Or rubber based; Known pressure-sensitive adhesives or adhesives such as pressure-sensitive adhesives or adhesives can be used without limitation. Specifically, the pressure-sensitive adhesive layer or the adhesive layer may be any one of a transparent adhesive film (OCA, Optically Clear Adhesive) and a pressure-sensitive silicone adhesive film PSA (Pressure Sensitive Adhesive), more specifically a pressure-sensitive silicone adhesive film (PSA, Pressure Sensitive Adhesive) can be used.

The optical element of the present application has the above structure, it is possible to prevent the phenomenon that the thermal stress caused by the difference in the coefficient of thermal expansion between each substrate. Accordingly, the thermal structural stability and durability of the optical element can be improved.

The third substrate may have a thermal expansion coefficient having an intermediate value between the thermal expansion coefficient value of the first substrate and the thermal expansion coefficient value of the second substrate. In this case, it is possible to secure the passion structural stability of the optical element.

In one example, the third substrate comprises a glass substrate; Crystalline or amorphous silicon films; Inorganic films such as quartz or ITO films; Or a plastic substrate.

In a specific example, the plastic substrate may include 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 Polyphenylsulfone (PPS), polyetherimide (PEI); polyethylenemaphthatlate (PEN); polyethyleneterephtalate (PET); polyimide (PI); polysulfone (PSF); polyarylate (PAR) or amorphous fluorine resin It doesn't happen.

The first substrate, the second substrate, and the third substrate may be the same kind of substrates, or may be different kinds of substrates.

In the present application, the liquid crystal layer may include a liquid crystal compound. The liquid crystal compound may be present in a switchable state in the liquid crystal layer. In the present specification, the switchable orientation may mean that the alignment direction of the liquid crystal compound may be changed by an external action such as application of a voltage. As the liquid crystal compound, for example, a smectic liquid crystal compound, a nematic liquid crystal compound, a cholesteric liquid crystal compound, or the like can be used. In addition, a liquid crystal compound having no polymerizable group or a crosslinkable group may be used as the liquid crystal compound so that the orientation is changed under an external action such as voltage from the outside.

The liquid crystal layer may further include an anisotropic dye. 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 region, for example, in the 400 nm to 700 nm wavelength range, and the term anisotropy The 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 anisotropic 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 the anisotropic dye, for example, a black dye can be used. Such dyes are known as, for example, azo dyes, anthraquinone dyes, and the like, but are not limited thereto.

The content of the anisotropic dye of the liquid crystal layer may be appropriately selected in consideration of the purpose of the present application. For example, the content of the anisotropic dye of the liquid crystal layer may be 0.1 wt% or more to 10 wt% or less. When the content of the anisotropic dye of the liquid crystal layer is in the above range, it is suitable to exhibit variable transmittance characteristics.

The alignment property of the liquid crystal compound in the liquid crystal layer may be changed by application of an external action.

In one example, in a state where there is no external action, when the liquid crystal layer is in a horizontal alignment, the transmittance may be increased by switching to a vertical alignment state by application of an external action.

In another example, in the absence of external action, the transmittance can be reduced by switching to the horizontal alignment state by the application of the external action when the liquid crystal layer is in vertical alignment. In addition, in the switching from the initial vertical alignment state to the horizontal alignment state, a pretilt in a predetermined direction may be required to determine the alignment direction of the liquid crystal compound. The manner in which the pretilt is imparted above is not particularly limited, and for example, it is possible to dispose an appropriate alignment film so as to impart the desired pretilt.

The present application relates to the use of the optical element. The optical device of the present application may be used as a variable transmittance member, the variable transmittance member may mean a variable transmittance film.

The variable transmittance film may be used, for example, as a retardation film or a viewing angle compensation film for a display device, a protective film of a polarizer, or the like.

The variable transmittance film of the present application can be applied to any device to which the variable transmittance can be applied. For example, the variable transmittance film of the present application may be applied to a sunroof, goggles, sunglasses or a helmet to provide a variable transmittance device. As long as the variable transmittance device includes the variable transmittance film of the present application, other parts or structures are not particularly limited, and all contents known in the art may be appropriately applied.

The optical device of the present application can effectively control the stress strengthening phenomenon and the deformation of the device that can occur according to the difference in physical properties between each layer.

1 is a structural diagram of an optical device according to an embodiment of the present application.
2 is a structural diagram of an optical device according to another embodiment of the present application.
4 is a structural diagram of an optical device according to a comparative example.

Hereinafter, the present application will be described in more detail with reference to examples, but the present invention is only an embodiment limited to the gist of the present application. On the other hand, the present application is not limited to the process conditions presented in the following examples, it can be arbitrarily selected within the range of conditions necessary to achieve the purpose of the present application is apparent to those skilled in the art. Do.

Example  One

After forming a PSA adhesive layer on the glass substrate layer, a known absorbing linear polarizing layer was formed. Then, after forming a PSA adhesive layer on the polarizing layer, a COP ITO film was formed as a first substrate. At this time, the PSA adhesive layer and the first substrate were formed narrower than the area of the polarizing layer. Then, a photo alignment layer was formed on the ITO film to induce horizontal alignment of the liquid crystal compound. Thereafter, the liquid crystal layer comprising an anisotropic dye (X12, manufactured by BASF) in an amount of 1 to 3 parts by weight based on 100 parts by weight of the liquid crystal compound (HPC21600, manufactured by HCCH) and the liquid crystal compound on the ITO film on which the photo alignment layer is formed. Was formed (about 15 mu m in thickness, ball spacers were used to maintain the thickness), and both sides were sealed with a second sealant. Then, after bonding the PET film as a second substrate having the same area as the polarizing layer on the liquid crystal layer, and sealing both sides of the second substrate and the polarizing layer with the first sealant to produce an optical device having a structure as shown in FIG. It was.

Example  2

2 and the same method as in Example 1 except that a COP or PC film was further formed between the polarizing layer and the first substrate using a PSA adhesive layer and a barrier layer, and the area of the barrier layer was the same as that of the first substrate. An optical device having the same structure was manufactured.

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Comparative example

An optical device having the structure as shown in FIG. 4 was manufactured in the same manner as in Example 1 except that the area of the first substrate was formed to be the same as that of the polarizing layer and the second substrate, and thus the first sealant was not used.

Test Example  1: durability test

The optical devices manufactured according to Examples 1 and 2 and Comparative Examples were allowed to stand at 120 ° C. for 240 hours, and then checked for damage or deformation of the liquid crystal window. Specifically, the damage of the device was visually confirmed, evaluated as O (with damage), X (without damage), shown in Table 1 below.

Example 1 Example 2 Comparative Example 1 LCD window broken X X O

According to Table 1, it can be seen that the optical device of the present application can prevent breakage and deformation of the device by preventing thermal stress due to the difference in coefficient of thermal expansion for each layer.

11: base layer
21, 22, 23: adhesive layer or adhesive layer
30: polarizing layer
41: first substrate
42: second substrate
51: first sealant
52: second sealant
60: liquid crystal layer
70: barrier layer

Claims (14)

Base layer;
A polarizing layer positioned on the base layer;
A first substrate on the polarizing layer;
A second substrate positioned on the first substrate; And
A liquid crystal layer present between the first substrate and the second substrate,
At least one of the base layer, the polarizing layer, and the second substrate has a larger area than the first substrate,
Further comprising a first sealant located on both sides between the polarizing layer and the second substrate,
Further comprising a second sealant located on both sides between the first substrate and the second substrate,
And the first substrate and the second substrate have different coefficients of thermal expansion (CTE).
The method of claim 1,
And the first substrate has a coefficient of thermal expansion (CTE) of less than 150 ppm / K.
The method of claim 1,
The polarizing layer is in direct contact with the substrate layer or is attached to the substrate layer via an adhesive layer or an adhesive layer.
The method of claim 1,
The first substrate is in direct contact with the polarizing layer or is attached to the polarizing layer via an adhesive layer or an adhesive layer.
delete The method of claim 1,
The first sealant has an elastic modulus of 20 GPa or less.
The method of claim 1,
An optical device further comprising a barrier layer between the polarizing layer and the first substrate.
The method of claim 7, wherein
The barrier layer is in direct contact with the polarizing layer and the first substrate, or is attached to the polarizing layer and the first substrate via an adhesive layer or an adhesive layer.
The method of claim 1,
And a third substrate between the polarizing layer and the first substrate.
The method of claim 9,
The third substrate is in direct contact with the polarizing layer and the first substrate, or is attached to the polarizing layer and the first substrate via an adhesive layer or an adhesive layer.
The method of claim 1,
The liquid crystal layer is an optical device comprising a smectic liquid crystal compound, a nematic liquid crystal compound or a cholesteric liquid crystal compound.
The method of claim 1,
The liquid crystal layer further comprises an anisotropic dye.
A variable transmittance member comprising the optical element according to claim 1.
A sunroof comprising the variable transmittance member according to claim 13.

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