Tint film

Abstract

The present specification discloses a tint film and uses thereof. The tint film is applied to a portion exposed to natural light, such as, for example, a glass window or glass wall of a building, glass of a vehicle, or eyewear. The tint film is applied to the portion to exhibit an intended function including imparting a color tone, does not cause optical defects such as the rainbow phenomenon, and stably maintains the color tone even when the viewing angle is changed. The tint film may exhibit the above-described performance even when combined with a variable-transmittance laminate in which transmittance changes according to the orientation of a liquid crystal compound.

Description

tint film

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-027115 dated February 28, 2025, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0002] This specification discloses a tint film and its uses.

[0003] Tint film is a film that is primarily attached to glass to provide specific functions. The functions of such tint film include one or more of the following: adjustment of transmittance, blocking of heat or ultraviolet rays, privacy protection, prevention of shattering in the event of glass breakage, anti-glare, and color correction.

[0004] The film commonly referred to as window tinting film is also a type of tint film.

[0005] Tint films are frequently used when exposed to natural light for functional purposes.

[0006] When a tint film with a phase difference is exposed to natural light, optical defects, sometimes referred to as the so-called rainbow phenomenon, may occur. Although not limited to theory, these optical defects are believed to be caused by interference phenomena induced when linearly polarized light, formed by natural light reflecting off surfaces such as ground or water, is incident on the tint film.

[0007] Patent Document 1 discloses that the above-mentioned insubstance phenomenon is resolved by applying a polymer film substrate with a high in-plane phase difference to a light modulation device exposed to natural light.

[0008] However, the light modulation device of Patent Document 1 does not include a tint film. A tint film is a film having a color tone and includes a dye or a pigment. Since such dyes or pigments absorb at least a portion of natural light, there is a difference between the optical phenomena that occur when a general film is exposed to natural light and the optical phenomena that occur when a tint film is exposed to natural light.

[0009] Therefore, there is a difference between the design for resolving optical defects such as rainbow phenomena in general films and the design for resolving the said optical defects in tint films.

[0010] Meanwhile, the tint film is manufactured to have a unique intended color tone, and this color tone must be maintained even when the viewing angle (angle of view) of the tint film changes, and this characteristic must be maintained even when exposed to natural light.

[0011] It is a difficult problem to prevent the occurrence of the above-mentioned optical defects in a tint film while simultaneously ensuring that the unique color tone of the tint film is maintained regardless of the viewing angle.

[0012] A tint film and a transmittance-variable laminate, in which transmittance changes depending on whether an external signal is applied, can be used in combination. The transmittance-variable laminate typically includes a liquid crystal compound to change transmittance depending on whether an external signal is applied.

[0013] Therefore, the combination of a tint film and a transmittance-variable laminate is a complex optical system involving the absorption of dyes or pigments within the tint film, the phase difference of the tint film, and the refractive index anisotropy of the liquid crystal compound. When the transmittance-variable laminate includes so-called PDLC (Polymer Dispersed Liquid Crystal) or the like for transmittance variability, the refractive index of the polymer within the PDLC also participates in the optical system.

[0014] Therefore, in the combination of the tint film and the transmittance-variable laminate, it is a more difficult problem to prevent optical defects such as rainbow phenomena and to maintain the color tone intended to be imparted through the use of the tint film regardless of the viewing angle.

[0015] <Prior Art Literature>

[0016] <Patent Literature>

[0017] (Patent Document 1) Korean Registered Patent No. 10-2176227

[0018] The present specification discloses a tint film and its uses. The tint film is applied to areas exposed to natural light, such as, for example, glass windows or glass walls of buildings; glass of automobiles; or eyewear. The tint film is applied to said areas to exhibit the intended function, including imparting a tint, without causing optical defects such as rainbows, and maintains the tint stably even when the viewing angle changes. The tint film can also exhibit said performance when combined with a transmittance-variable laminate in which the transmittance changes according to the orientation of the liquid crystal compound.

[0019] This specification also discloses the use of the tint film.

[0020] Among the physical properties described in this specification, those affected by the measurement temperature are properties measured at room temperature unless specifically otherwise defined.

[0021] The term room temperature refers to a natural temperature that has not been artificially heated or cooled, and may refer to, for example, any temperature within the range of 10°C to 30°C or a temperature of about 23°C or about 25°C.

[0022] In this specification, the unit of temperature is Celsius (°C) unless specifically otherwise specified.

[0023] Among the physical properties described in this specification, those affected by the measurement pressure are properties measured at atmospheric pressure, unless otherwise specifically defined.

[0024] The term atmospheric pressure refers to natural pressure that has not been artificially pressurized or depressurized, and typically refers to any pressure within the range of about 730 mmHg to 790 mmHg.

[0025] Among the physical properties mentioned in this specification, those affected by the measured humidity are physical properties measured at humidity that is not specifically adjusted under the above-mentioned ambient temperature and pressure conditions, unless otherwise specifically defined.

[0026] This specification discloses a tint film.

[0027] The above tint film includes a phase difference layer and a tint layer. The tint layer may be laminated or formed on one or both sides of the phase difference layer. FIG. 1 is a side view of an exemplary tint film in which the tint layer (100) is formed on one side of the phase difference layer (201).

[0028] The above phase difference layer may have an in-plane phase difference of a certain level or higher.

[0029] The method for measuring or verifying the in-plane phase difference, the thickness direction phase difference, and the Nz value is described in "1. Phase Difference Evaluation" of the Examples section of this specification.

[0030] In addition, the reference wavelength of the refractive index, in-plane phase difference, thickness direction phase difference and Nz in this specification is 550 nm unless specifically otherwise specified.

[0031] The lower limit of the in-plane phase difference of the above phase difference layer may be approximately 1 μm, 2 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, or 10 μm, and the upper limit may be approximately 100 μm, 80 μm, 60 μm, 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 18 μm, 16 μm, 15 μm, 14 μm, 13 μm, 12 μm, 11 μm, or 10 μm. The in-plane phase difference of the phase difference layer may be within a range greater than or exceeding any lower limit selected from the lower limits listed above; or within a range greater than or exceeding any lower limit selected from the lower limits listed above, and less than or equal to any upper limit selected from the upper limits listed above.

[0032] These phase difference layers may have the characteristics of a so-called +A film (phase difference layer satisfying Equation A below), -A film (phase difference layer satisfying Equation B below), +B film (phase difference layer satisfying Equation C below), Z film (phase difference layer satisfying Equation D below), or -B film (phase difference layer satisfying Equation E below).

[0033] [Equation A]

[0034] n x > n y = n z

[0035] [Equation B]

[0036] n x =n z >n y

[0037] [Equation C]

[0038] n z >n x >n y

[0039] [Essence D]

[0040] n x>n z >n y

[0041] [E]

[0042] n x >n y >n z

[0043] n in formulas A to E x , n y and n z is the ground axis direction refractive index, leading axis direction refractive index, and thickness direction refractive index of each phase difference layer.

[0044] The above refractive index may be a refractive index based on a wavelength of 550 nm.

[0045] When the phase difference layer is a -B film, the desired effect can be secured more appropriately.

[0046] A method of resolving optical defects such as rainbow phenomena by adjusting the in-plane phase difference of the phase difference layer is also known in Patent Document 1. However, Patent Document 1 focuses only on the in-plane phase difference of the phase difference layer. However, when applied to a film that exhibits light absorption by dyes or pigments, such as a tint film, the above performance cannot be stably achieved solely by adjusting the in-plane phase difference.

[0047] In order for the above tint film to exhibit the intended performance, it is necessary to control the in-plane phase difference of the phase difference layer along with the phase difference layer in the thickness direction, and additionally, control of the characteristics of the tint layer is also required.

[0048] Accordingly, the above phase difference layer can have a controlled Nz value.

[0049] For example, the lower limit of the Nz value of the phase difference layer may be -1, -0.95, -0.9, -0.85, -0.8, -0.75, -0.7, 0.65, -0.6, -0.55, or -0.5, and the upper limit may be 20, 18, 16, 14, 12, 10, 8, 7, 6, 4, 3, 2, 1.5, 1, 0.5, 0, -0.05, -0.1, -0.15, -0.2, -0.25, -0.3, -0.35, -0.4, -0.45, -0.5, -0.55, -0.6, -0.65, -0.7, -0.75, -0.8, -0.85, -0.9, -0.95, or It may be approximately -1. The above Nz is the ratio Rth / Rin of the thickness direction phase difference Rth to the in-plane phase difference Rin of the above phase difference layer, and a method for verifying this is described in the example section. The above Nz value may be within a range greater than or greater than any lower limit selected from the listed lower limits; or within a range greater than or greater than any lower limit selected from the listed lower limits, and less than or less than any upper limit selected from the listed upper limits.

[0050] The lower limit of the phase difference Rth in the thickness direction of the above-mentioned phase difference layer may be approximately -50 μm, -45 μm, -40 μm, -35 μm, -30 μm, -25 μm, -20 μm, -15 μm, -13 μm, or -10 μm, and the upper limit may be approximately 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm, 10 μm, 5 μm, 0 μm, -2 μm, -4 μm, -6 μm, -8 μm, or -10 μm. The above-mentioned phase difference in the thickness direction is within a range greater than or exceeding any lower limit arbitrarily selected from the listed lower limits; or within a range less than or equal to any upper limit arbitrarily selected from the listed upper limits. Or it may be within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above, and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0051] The phase difference layer can have an appropriate level of thickness.

[0052] The lower limit of the thickness of the phase difference layer may be approximately 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, or 80 μm, and the upper limit may be approximately 300 μm, 250 μm, 200 μm, 150 μm, or 100 μm. The thickness may be within a range greater than or equal to any one of the lower limits listed above, and less than or equal to any one of the upper limits listed above.

[0053] A known phase difference film exhibiting the above characteristics may be applied as the phase difference layer.

[0054] There are no specific limitations on the specific type of the above-mentioned phase difference layer as long as it exhibits the in-plane phase difference, etc. mentioned above. For example, an anisotropic polymer film or sheet, a liquid crystal film, or a liquid crystal coating layer that imparts optical anisotropy by stretching may be used as the above-mentioned phase difference layer. Examples of polymer films include polyolefin films such as polyethylene films or polypropylene films, cycloolefin polymer (COP) films such as polynorbornene films, polyvinyl chloride films, polyacrylonitrile films, polysulfone films, polyacrylate films, cellulose ester-based polymer films such as PVA (poly(vinyl alcohol)) films or TAC (triacetyl cellulose) films, polyester films, or polycarbonate films, or copolymer films of two or more monomers among the monomers forming the above-mentioned polymers. Additionally, the liquid crystal film or liquid crystal coating layer is a phase difference layer formed using a liquid crystal polymer or using a polymerizable liquid crystal (so-called RM (Reactive MEsogen)).

[0055] For example, a stretched polymer film formed to have the phase difference characteristics described above may be applied, and examples thereof may include an olefin film such as a COP (Cyclo-Olefin Polymer) film, a cellulose film such as a TAC (Triacetyl Cellulose) film, a PC (polycarbonate) film, a polyester film such as a PET (poly(ethylene terephthalate)) film, or an acrylic film such as a PMMA (Polymethyl Methacrylate) film.

[0056] Patent document 1 also uses a stretched polymer film, for example, a stretched PET (poly(ethylene terephthalate)) film. However, the stretched PET film of patent document 1 focuses only on the in-plane phase difference Rin and does not consider the thickness direction phase difference Rth.

[0057] In order for the phase difference layer, which is a stretched polymer film, to exhibit the desired Nz value, additional measures such as controlling the stretching conditions are required.

[0058] For example, as a polymer material, it is advantageous to use a material having positive birefringence, such as PC (polycarbonate), PET (poly(ethylene terephthalate)), or COP (Cyclo-Olefin Polymer), to obtain the desired phase difference layer. However, the application of such materials alone cannot apply the Nz value to the above range. To adjust the Nz value, for example, measures such as preventing shrinkage of the material in the TD (Transverse Direction) direction by utilizing a fixing means while performing strong stretching in the MD (Machine Direction) direction during a uniaxial stretching process, or applying a weak stretching force in the TD direction; or a biaxial stretching process in which the film of the above material is strongly stretched in the MD direction and additionally weak stretching is performed in the TD direction must be applied.

[0059] Including the above method, the method of adjusting Rin and Rth of the phase difference layer itself is well known.

[0060] The tint layer formed on one or both sides of the phase difference layer in the tint film may include a coloring agent such as a pigment and / or dye as a layer that imparts a color tone.

[0061] The color tone imparted to the tint layer can be adjusted, and the intended performance can be achieved by combining this tint layer with the phase difference layer.

[0062] For example, the tint layer may be provided to exhibit a controlled transmittance.

[0063] For example, the upper limit of the transmittance (based on a wavelength of 550 nm) of the tint layer or the tint film containing it may be approximately 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, or 30%, and the lower limit may be approximately 0%, 1%, 5%, 10%, 15%, 20%, or 25%. The transmittance may be within a range less than or equal to any one of the upper limits listed above; or greater than or equal to any one of the lower limits listed above, while being within a range less than or equal to any one of the upper limits listed above.

[0064] The above transmittance may be direct light transmittance. Direct light transmittance is the percentage of the ratio of light transmitted in the same direction as the incident direction to light incident on the tint layer. For example, among the light incident in a direction parallel to the normal direction of the surface of the tint layer, the percentage of light transmitted through the tint layer in a direction parallel to the normal direction can be defined as the transmittance. Such transmittance can be measured with known equipment such as an Axoscan.

[0065] The L* of the CIE Lab* color space of the tint layer or the tint film containing it can be adjusted.

[0066] The lower limit of the above L* may be, for example, 5, 10, 15, 20, 25, or 30, and the upper limit may be 60, 55, 50, 45, 40, 35, or 30. The above L* may be within a range that is greater than or equal to any one of the lower limits listed above, and less than or equal to any one of the upper limits listed above.

[0067] The a* of the CIE Lab* color space of the tint layer or the tint film containing it can be adjusted.

[0068] The lower limit of the above a* may be, for example, -10, -9.5, -9, -8.5, -8, -7.5, -7, -6.5, -6, -5.5, -5, -4.5, -4, -3.5, -3, -2.5, -2, -1.5, -1, or -0.5, and the upper limit may be 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, or 0.5. The above a* may be within a range greater than or equal to any one of the lower limits listed above, and less than or equal to any one of the upper limits listed above.

[0069] The b* of the CIE Lab* color space of the tint layer or the tint film containing it can be adjusted.

[0070] The lower limit of the above b* may be, for example, -10, -9.5, -9, -8.5, -8, -7.5, -7, -6.5, -6, -5.5, -5, -4.5, -4, -3.5, -3, -2.5, -2, -1.5, -1, or -0.5, and the upper limit may be 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, or 0.5. The above a* may be within a range greater than or equal to any one of the lower limits listed above, and less than or equal to any one of the upper limits listed above.

[0071] Each value of the above CIE Lab* color space can be verified in reflection mode, for example, using a HunterLab UltraScan PRO Spectrophotometer. For example, the above values ​​can be obtained using the above equipment and / or according to the KS A 006 standard.

[0072] The L*, a*, and b* and transmittance of the above CIE Lab* color space are determined by the extent to which the tint layer absorbs light of a certain wavelength. That is, a tint layer having the above transmittance and characteristics of the CIE Lab* color space can be combined with the aforementioned phase difference layer to provide a desired tint film.

[0073] As such a tint layer, any known tint layer may be applied without special limitations. Typically, a tint layer can be obtained by coating a material obtained by combining a coloring agent (pigment and / or dye) with a binder resin and combining it with other necessary additives (e.g., UV blockers, infrared absorbers, light stabilizers and / or solvents, etc.), and, if necessary, undergoing drying and curing processes. In this process, a tint layer exhibiting the transmittance and characteristics of the CIE Lab* color space can be obtained by adjusting the type and amount of the coloring agent (pigment and / or dye) in consideration of other materials such as the binder resin.

[0074] In one example, the tint layer may be a resin layer. For example, the resin layer may be applied as a tint layer by coloring it according to the purpose using dyes or pigments. Such a resin layer may be, for example, an acrylic resin layer or a silicone resin layer. Depending on the purpose, such a tint layer may additionally contain known additives required for a tint layer, such as UV blockers and / or UV absorbers.

[0075] In one example, the tint layer may be an adhesive layer or an adhesive layer. For example, a tint layer exhibiting the characteristics described above can be obtained by incorporating a suitable coloring agent into the adhesive layer or adhesive layer.

[0076] The tint layer can have an appropriate thickness.

[0077] For example, the lower limit of the thickness of the tint layer may be approximately 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, and the upper limit may be approximately 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm, or 10 μm. The thickness may be within a range greater than or equal to any one of the lower limits listed above, and less than or equal to any one of the upper limits listed above.

[0078] The tint film may include other components additionally required for the phase difference layer and the tint layer.

[0079] For example, the tint film may include an additional phase difference layer formed on the side where the phase difference layer is not formed. In this case, the phase difference layer described above may be called phase difference layer A, and the additional phase difference layer may be called phase difference layer B.

[0080] FIG. 2 is an exemplary cross-sectional view of the case where the phase difference layer B (202) is added.

[0081] While a known phase difference layer may be applied as the above phase difference layer B, a phase difference layer of the same type as the above phase difference layer A may be applied to effectively achieve the desired performance. In such cases, the details regarding the in-plane phase difference, Nz value, thickness, material, etc., of the phase difference layer B may be the same as those described for the phase difference layer A.

[0082] In this way, when two phase difference layers are applied, the relationship of the slow axis between phase difference layer A and phase difference layer B can be adjusted.

[0083] For example, when phase difference layers A and B are applied, the lower limit of the angle formed by the ground axes of the two phase difference layers may be approximately 0 degrees, 2 degrees, 4 degrees, 6 degrees, 8 degrees, 10 degrees, 15 degrees, or 20 degrees, and the upper limit may be approximately 20 degrees, 15 degrees, 10 degrees, 8 degrees, 6 degrees, 4 degrees, 2 degrees, or 0 degrees. The angle may be within a range that is greater than or equal to any one of the lower limits listed above, and less than or equal to any one of the upper limits listed above.

[0084] In another example, when phase difference layers A and B are applied, the lower limit of the angle formed by the ground axes of the two phase difference layers may be approximately 80 degrees, 82 degrees, 84 degrees, 86 degrees, 88 degrees, 90 degrees, 95 degrees, or 100 degrees, and the upper limit may be approximately 100 degrees, 98 degrees, 96 degrees, 94 degrees, 92 degrees, 90 degrees, 85 degrees, or 80 degrees. The angle may be within a range that is greater than or equal to any one of the lower limits listed above, and less than or equal to any one of the upper limits listed above.

[0085] The tint film may additionally include a separate adhesive layer or adhesive layer for applying the tint film to other parts, for example, when the tint layer is not an adhesive layer or adhesive layer, or when it has a structure as shown in FIG. 2.

[0086] These tint films can be applied for their intended purpose on their own, or in combination with so-called transmittance-variable laminates.

[0087] The term transmittance-variable laminate refers to a laminate in which the transmittance can be reversibly changed depending on whether an external signal (e.g., an external electrical signal) is applied.

[0088] Such a transmittance-variable laminate includes a transmittance-variable layer as a layer that enables a reversible change in transmittance.

[0089] Accordingly, the transmittance-variable laminate to which the tint film is applied may include the tint film; and a transmittance-variable layer formed on one surface of the tint film.

[0090] By applying the tint film, the laminate does not exhibit optical defects such as rainbows even when exposed to natural light, and can stably maintain the intended color tone even when the viewing angle changes.

[0091] For example, the laminate above can have △E of the following Equation 1 controlled within a predetermined range.

[0092] [Equation 1]

[0093] △E = [(L*-L*') 2 +(a*-a*') 2 +(b*-b*') 2 ] 0.5

[0094] In Equation 1, L* is the L* value of the stacked body confirmed with the azimuth angle set to 0 degrees and the polar angle set to 0 degrees.

[0095] In Equation 1, a* is the a* value of the stacked body confirmed with the azimuth angle set to 0 degrees and the polar angle set to 0 degrees.

[0096] In Equation 1, b* is the b* value of the stacked body confirmed with the azimuth angle set to 0 degrees and the polar angle set to 0 degrees.

[0097] In Equation 1, L*' is the L* value of the stacked body confirmed with the azimuth angle set to 0 degrees and the polar angle set to 60 degrees.

[0098] In Equation 1, a*' is the a* value of the above stacked body confirmed with an azimuth angle of 0 degrees and a polar angle of 60 degrees.

[0099] In Equation 1, b*' is the b* value of the stacked body confirmed with the azimuth angle set to 0 degrees and the polar angle set to 60 degrees.

[0100] A method for verifying △E of Formula 1 is described in "Test Example 1" of the Examples section of this specification.

[0101] The upper limit of △E in Equation 1 may be approximately 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, or 4.5, and the lower limit may be approximately 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5. The above △E may be within a range less than or equal to any upper limit selected from the listed upper limits; or greater than or equal to any lower limit selected from the listed lower limits, and within a range less than or equal to any upper limit selected from the listed upper limits.

[0102] A laminate in which △E is controlled within the above range can stably maintain the intended color tone even when the viewing angle changes.

[0103] Various types of such variable transmittance layers can be applied. In one example, a layer comprising a polymer and a liquid crystal can be applied as the variable transmittance layer. This variable transmittance layer may be a layer in which the transmittance changes according to an external signal by adjusting the difference in refractive index between the polymer and the liquid crystal. For example, the variable transmittance layer may be a layer known as PDLC (Polymer Dispersed Liquid Crystal), PNLC (Polymer Network Liquid Crystal), or PSLC (Polymer Stabilized Liquid Crystal).

[0104] In this variable transmittance layer, the effect of combination with the tint film can be maximized by adjusting the relationship between the polymer and the liquid crystal's refractive index and the size of the droplets within the variable layer.

[0105] For example, the lower limit of the ratio of the total weight of the polymer and the liquid crystal based on the total weight of the variable transmittance layer may be approximately 80 wt%, 85 wt%, 90 wt%, or 95 wt%, and the upper limit may be approximately 100 wt%. The ratio may be within a range greater than or equal to any one of the lower limits listed above, and less than or equal to the upper limit.

[0106] The lower limit of the ratio of the polymer based on the total weight of the variable transmittance layer may be approximately 2, 5, 10, 15, 20, 25, 30, 35, 40, or 45, and the upper limit may be approximately 90, 85, 80, 75, 70, 65, 60, 55, 50, or 45. The unit of the ratio is weight%. The ratio may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0107] As the liquid crystal mentioned above, known smectic liquid crystals, nematic liquid crystals, or cholesteric liquid crystals may be used without any particular limitations. Such liquid crystals may exist in a state where their orientation can be changed within the polymer depending on the presence or absence of an external signal. Transmittance can be controlled according to this change in the orientation of the liquid crystal. For example, if the orientation of the liquid crystal is not regular and is random, scattering of light can be induced through interaction with the polymer. When an external signal is applied to align the liquid crystal in a unidirectional manner, a different transmittance compared to the random case can be exhibited through the interaction of the refractive index of the oriented liquid crystal and the polymer.

[0108] In one example, a so-called nematic liquid crystal can be used as the liquid crystal mentioned above.

[0109] In order to achieve the desired effect, the above liquid crystal has the so-called normal refractive index n of the liquid crystal. o and the anomalous refractive index n e A liquid crystal with a deviation within a predetermined range can be used. The deviation △n of the refractive index is determined by the following Equation 2, and the reference wavelength of the refractive index is 550 nm.

[0110] [Equation 2]

[0111] △n = 100 × (n e -n o ) / n o

[0112] n in Equation 2 e is the abnormal refractive index of the liquid crystal, and n o is the normal refractive index of the liquid crystal.

[0113] The lower limit of △n in Equation 2 may be approximately 0.5%, 2%, 4%, 6%, 8%, 10%, 12%, or 14%, and the upper limit may be approximately 50%, 45%, 40%, 35%, 30%, 25%, 20%, or 15%. The above △n may be within a range greater than or equal to any lower limit selected from the listed lower limits, and less than or equal to any upper limit selected from the listed upper limits.

[0114] As liquid crystals, when two or more types of liquid crystals are applied, both of the two types of liquid crystals may be liquid crystals in which △n of Equation 2 is adjusted to the above range, and at least one of the two types of liquid crystals may be a liquid crystal in which △n of Equation 2 is adjusted to the above range.

[0115] For example, the lower limit of the ratio of the weight of the liquid crystal adjusted to the above range, based on the total weight of the liquid crystal applied to the variable transmittance layer, may be approximately 50 wt%, 60 wt%, 70 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt%, and the upper limit may be approximately 100 wt%. The above ratio may be within a range greater than or equal to any one of the lower limits listed above, and less than or equal to the upper limit.

[0116] There are no specific restrictions on the type of polymer present in the variable transmittance layer. In one example, the polymer may be an acrylic polymer. The term "acrylic polymer" refers to a polymer containing a polymerization unit of an acrylic monomer. The term "acrylic monomer" refers to acrylic acid, methacrylic acid, acrylic acid ester, or methacrylic acid ester. Additionally, the so-called polyfunctional acrylate described below may also be an example of an acrylic monomer. Furthermore, the term "polymerization unit" refers to the state in which a monomer is included in the polymer as it undergoes a polymerization process to form a polymer.

[0117] In one example, the lower limit of the ratio of the polymerization units of the acrylic monomer based on the total weight of the polymerization units included in the polymer may be approximately 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt%, and the upper limit may be approximately 100 wt%. The ratio may be within a range greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to the upper limit.

[0118] In one example, the polymer may include a unit of the following chemical formula 1 as a polymerization unit of the acrylic monomer.

[0119] [Chemical Formula 1]

[0120]

[0121] In Chemical Formula 1, R1 is hydrogen or an alkyl group, and R2 may be a branched alkyl group.

[0122] The alkyl group of R1 may be an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, or a methyl group. The alkyl group may be a straight chain, a branched chain, or a cyclic type.

[0123] R2 of Chemical Formula 1 above may be a branched alkyl group. The lower limit of the number of carbon atoms of such a branched alkyl group may be 3, 4, 5, 6, 7, or 8, and the upper limit may be approximately 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, or 8. The number of carbon atoms of the branched alkyl group may be within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above, and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0124] Examples of the above branched alkyl groups include ethylhexyl groups, but are not limited thereto.

[0125] The lower limit of the ratio of the polymerization unit of Formula 1 based on the total weight of the total polymerization unit of the polymer may be approximately 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%, and the upper limit may be approximately 90 wt%, 85 wt%, 80 wt%, 75 wt%, 70 wt%, 65 wt%, 60 wt%, 55 wt%, or 50 wt%. The ratio may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0126] The above polymer may also include a unit of the following chemical formula 2 as a polymerization unit of the above acrylic monomer.

[0127] [Chemical Formula 2]

[0128]

[0129] In Chemical Formula 2, R1 is the same as R1 in Chemical Formula 1.

[0130] In Chemical Formula 2, R3 can be a cycloalkyl group, a bicycloalkyl group, or a tricycloalkyl group.

[0131] The number of carbon atoms in the cycloalkyl group may be in the range of 3 to 15. Specific examples of such cycloalkyl groups include at least one selected from the group consisting of cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptanyl group, cyclooctyl group, cyclodecanyl group and / or cyclododecanyl group.

[0132] Bicycloalkyl groups and tricycloalkyl groups may be functional groups having a cross-linked structure in which two positions of a polycyclic compound are connected by a linear carbon chain. The number of carbon atoms in these bicycloalkyl groups and tricycloalkyl groups may each be within the range of 5 to 30. Examples of the bicycloalkyl groups include isobornyl groups and / or bicyclo[3.2.1]octyl groups, etc., and examples of the tricycloalkyl groups include dicyclofentanyl groups and / or tricyclodecane groups, etc., but are not limited thereto.

[0133] The lower limit of the ratio of the polymerization unit of Formula 2 based on the total weight of the total polymerization unit of the polymer may be approximately 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%, and the upper limit may be approximately 80 wt%, 75 wt%, 70 wt%, 65 wt%, 60 wt%, 55 wt%, 50 wt%, 45 wt%, or 40 wt%. The ratio may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0134] The polymer may include the polymerization unit of Formula 1 and the polymerization unit of Formula 2 together. In this case, the lower limit of the weight ratio of the polymerization unit of Formula 2 to 100 parts by weight of the polymerization unit of Formula 1 may be approximately 10 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight, or 75 parts by weight, and the upper limit may be approximately 200 parts by weight, 150 parts by weight, 100 parts by weight, 90 parts by weight, or 85 parts by weight. The ratio may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0135] The above polymer may include polymerization units of polyfunctional acrylate to realize a cross-linked structure as needed. In this specification, the polyfunctional acrylate is also a type of acrylic monomer. As the polyfunctional acrylate, known compounds may be used without particular limitation.For example, the above-mentioned polyfunctional acrylates include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxyl puivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, di(meth)acryloxyethyl isocyanurate, and allylated cyclohexyl Difunctional acrylates such as di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, ethylene oxide-modified hexahydrophthalic acid di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, neopentyl glycol-modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate, or 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, etc.; Trifunctional acrylates such as trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate, or tris(meth)acryloxyethyl isocyanurate; tetrafunctional acrylates such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; pentafunctional acrylates such as propionic acid-modified dipentaerythritol penta(meth)acrylate; and dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate or urethane (meth)acrylate (ex.Examples include hexafunctional acrylates such as isocyanate monomers and reactants of trimethylolpropane tri(meth)acrylate, but are not limited thereto.

[0136] In one example, the polyfunctional acrylate suitable for the laminate disclosed herein may be an acrylate having a molecular weight within a predetermined range. For example, the lower limit of the molecular weight may be approximately 50, 150, or 200, and the upper limit may be approximately 1,000, 800, 600, 400, or 300. The molecular weight may be within a range greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits. The unit of the molecular weight is g / mol.

[0137] As such polyfunctional acrylates, difunctional, trifunctional, or tetrafunctional acrylates can be used.

[0138] The lower limit of the ratio of the polymerization units of the polyfunctional acrylate based on the total weight of the total polymerization units of the polymer may be approximately 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.7 wt%, 0.9 wt%, or 1 wt%, and the upper limit may be approximately 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1.5 wt%, or 1 wt%. The ratio may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0139] The polymer may include the polymerization unit of Formula 1 and the polymerization unit of the polyfunctional acrylate together. In this case, the lower limit of the weight ratio of the polymerization unit of the polyfunctional acrylate to 100 parts by weight of the polymerization unit of Formula 1 may be approximately 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, or 20 parts by weight, and the upper limit may be approximately 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 parts by weight, 30 parts by weight, 25 parts by weight, or 20 parts by weight. The ratio may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0140] The polymer essentially comprises one of the polymerization units and, if necessary, may also comprise other polymerization units.

[0141] The total polymerization units included in the polymer can be selected such that the weight-average refractive index of the said polymerization units is within a predetermined range. By making such a selection, the laminate can more appropriately achieve the desired effect.

[0142] For example, the lower limit of the weight-average refractive index may be approximately 1.00, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, or 1.44, and the upper limit may be approximately 1.7, 1.65, 1.6, 1.55, 1.5, or 1.45. The weight-average refractive index may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0143] The weight-average refractive index can be determined by considering the refractive index of each monomer forming the polymerization unit and the ratio of the said monomers. For example, the monomers forming the polymer are monomers A, B, and C, and the refractive index of each monomer is n A , n B and n C and the content of each monomer is w A , w B and w C Ramen, the above weight-average refractive index is given by the formula (n A× w A +n B× w B +n C× w C ) / (w A +w B +w C It is calculated as ). In the above, the refractive index of the monomer is the n20 / D refractive index. In the industry, the above n20 / D refractive index of a general-purpose monomer is well known. In addition, in the above, the ratio w A , w B and w C is a percentage, and therefore its sum is 100.

[0144] In one example, the deviation between the refractive index of the liquid crystal included in the variable transmittance layer and the weight-average refractive index can be set within an appropriate range.

[0145] For example, the liquid crystal and polymer can be selected such that △R of Formula 3 below is within a predetermined range.

[0146] [Equation 3]

[0147] △R = 100 × (n LC -n p ) / n p

[0148] n in Equation 3 LC is the anomalous refractive index of the liquid crystal based on a wavelength of 550 nm, and n p is the above-mentioned weight-average refractive index.

[0149] For example, the lower limit of the absolute value of △R in Equation 3 above may be approximately 0.5%, 2%, 4%, 6%, 8%, 10%, 12%, 16%, 18%, or 19%, and the upper limit may be approximately 50%, 45%, 40%, 35%, 30%, 25%, or 20%. The absolute value of △R may be within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above, and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. △R may be positive or negative.

[0150] The above polymer and the liquid crystal satisfying the above △R may be, for example, a liquid crystal in which △n of the above Equation 2 is within a predetermined range.

[0151] The size of the droplet in the above-described variable transmittance layer can be controlled. For example, the lower limit of the droplet size may be approximately 0.01 μm, 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, or 1.3 μm, and the upper limit may be approximately 10 μm, 8 μm, 6 μm, 4 μm, 2 μm, or 1.5 μm. The size of the droplet may be within a range greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0152] The size of the above droplet is the size of the droplet when the transmittance variable layer is a so-called PDLC (Polymer Dispersed Liquid Crystal), PNLC (Polymer Network Liquid Crystal), or PSLC (Polymer Stabilized Liquid Crystal), and can be confirmed through a SEM (Scanning Electron Microscope).

[0153] The thickness of the variable transmittance layer can also be determined by considering effects such as the desired transmittance.

[0154] For example, the lower limit of the thickness of the variable transmittance layer may be approximately 0.01 μm, 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, or 20 μm, and the upper limit may be approximately 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, or 20 μm. The thickness may be within a range greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0155] FIG. 3 is an exemplary cross-sectional view of a transmittance-variable laminate to which the tint film is applied.

[0156] As shown in FIG. 3, the laminate may include a first phase difference layer (1001); a first tint layer (2001) located below the first phase difference layer; a second phase difference layer (1002) located below the first tint layer; a transmittance variable layer (3000) located below the second phase difference layer; a third phase difference layer (1003) located below the transmittance variable layer; a second tint layer (2002) located below the third phase difference layer; and a fourth phase difference layer (1004) located below the second tint layer.

[0157] The specific description of the variable transmittance layer and the tint layer in the above structure is as described above.

[0158] Meanwhile, at least one of the first to fourth phase difference layers included in the laminate may be a phase difference layer of the tint film described above.

[0159] For example, in the above structure, the stacked structure of the first or second phase difference layer and the tint layer and / or the stacked structure of the third or fourth phase difference layer and the tint layer may be a structure derived from the tint film described above, and in this case, the phase difference layer may have the characteristics described above.

[0160] For example, one or more, two or more, three or more, or all of the first to fourth phase difference layers described above may be phase difference layers having the in-plane phase difference and Nz value, etc.

[0161] If there is a layer among the above phase difference layers that is not a phase difference layer having the in-plane phase difference and Nz value described above, there are no special restrictions on the type of such phase difference layer, and a general phase difference layer in such a case may be used.

[0162] The arrangement of the ground axis between the first to fourth phase difference layers in the above laminate can be adjusted.

[0163] In one example, the ground axes of the above phase difference layers can be horizontal or vertical to each other.

[0164] The term "horizontal" means a case where the smaller angle among the angles formed by two axes is within a predetermined range. In this case, the lower limit of the smaller angle may be approximately 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 degrees, and the upper limit may be approximately 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or 10 degrees. When the two axes are horizontal, the smaller angle may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0165] The term "perpendicular" means a case where the smaller of the angles formed by two axes is within a predetermined range. In this case, the lower limit of the smaller angle may be approximately 80 degrees, 81 degrees, 82 degrees, 83 degrees, 84 degrees, 85 degrees, 86 degrees, 87 degrees, 88 degrees, 89 degrees, or 90 degrees, and the upper limit may be approximately 100 degrees, 99 degrees, 98 degrees, 97 degrees, 96 degrees, 95 degrees, 94 degrees, 93 degrees, 92 degrees, 91 degrees, or 90 degrees. When the two axes are perpendicular, the smaller angle may be within a range that is greater than or equal to any lower limit arbitrarily selected from the listed lower limits, and less than or equal to any upper limit arbitrarily selected from the listed upper limits.

[0166] As mentioned above, in the above example, the ground axes of the phase difference layers can be horizontal or vertical to each other.

[0167] Accordingly, for example, in the above laminate, the ground axis of the first phase difference layer and the ground axis of the second phase difference layer may be perpendicular or horizontal to each other.

[0168] For example, in the above structure, the ground axis of the first phase difference layer and the ground axis of the third phase difference layer may be perpendicular or horizontal to each other.

[0169] For example, in the above structure, the ground axis of the first phase difference layer and the ground axis of the fourth phase difference layer may be perpendicular or horizontal to each other.

[0170] The above laminate may include additional configurations necessary for the above configuration.

[0171] For example, the laminate may additionally include an electrode layer as a layer for applying an external signal to the variable transmittance layer. Such an electrode layer may be formed on one or both sides of the variable transmittance layer. For example, in the structure of FIG. 3, the electrode layer may exist between the second phase difference layer (1002) and the variable transmittance layer (3000) and / or between the third phase difference layer (1003) and the variable transmittance layer (3000). As the electrode layer, for example, a known transparent electrode layer such as ITO (Indium Tin Oxide) may be applied.

[0172] The above laminate may additionally include an alignment layer for aligning the liquid crystal layer included in the transmittance variable layer. In some cases, the alignment layer may not be present in the laminate. For example, in the structure of FIG. 1, the alignment layer may be present between the second phase difference layer (1002) and the transmittance variable layer (3000) and / or between the third phase difference layer (1003) and the transmittance variable layer (3000).

[0173] The above laminate may also include additional phase difference layers. The structure of the laminate including such additional layers is illustrated in FIG. 4. That is, for example, the laminate may additionally include a fifth phase difference layer (1005) between the second phase difference layer (1002) and the transmittance variable layer (3000), and a sixth phase difference layer (1006) between the third phase difference layer (1003) and the transmittance variable layer (3000). These fifth and / or sixth phase difference layers may be phase difference layers having the in-plane phase difference and Nz value, etc. described above, or general phase difference layers.

[0174] When the above-mentioned 5th and 6th phase difference layers are added, the ground axes of the 5th and 6th phase difference layers may be horizontal or vertical to each other, and the ground axis of the 5th phase difference layer and the ground axis of another phase difference layer (e.g., the 1st phase difference layer) may be horizontal or vertical to each other.

[0175] The tint film or laminate can be used for various purposes. For example, the tint film or laminate can be used as a window exposed to an external light source, such as a glass window or glass wall of a building; glass of a car; or eyewear, or can be attached to the window.

[0176] Accordingly, the present specification also discloses a building, automobile, or eyewear comprising the tint film or transmittance-variable laminate in glass.

[0177] These tint films or transmittance-variable laminates can be used as glass for the building, automobile, or eyewear, or can be attached to the glass.

[0178] The present specification discloses a tint film and its uses. The tint film is applied to areas exposed to natural light, such as, for example, glass windows or glass walls of buildings; glass of automobiles; or eyewear. The tint film is applied to said areas to exhibit the intended function, including imparting a tint, without causing optical defects such as rainbows, and maintains the tint stably even when the viewing angle changes. The tint film can also exhibit said performance when combined with a transmittance-variable laminate in which the transmittance changes according to the orientation of the liquid crystal compound.

[0179] Figure 1 is an exemplary cross-sectional view of a tint film.

[0180] Figure 2 is an exemplary cross-sectional view of a tint film.

[0181] Figure 3 is an exemplary cross-sectional view of a laminate.

[0182] Figure 4 is an exemplary cross-sectional view of a laminate.

[0183] Figure 5 is a polar plot for Example 4.

[0184] Figure 6 is a polar plot for Example 5.

[0185] Figure 7 is a polar plot for Example 6.

[0186] Figure 8 is a polar plot for Comparative Example 4.

[0187] Figure 9 is a polar plot for Comparative Example 5.

[0188] Figure 10 is a polar plot for Comparative Example 6.

[0189] Figure 11 is a chromaticity graph for Example 4.

[0190] Figure 12 is a chromaticity graph for Example 5.

[0191] Figure 13 is a chromaticity graph for Example 6.

[0192] Figure 14 is a chromaticity graph for Comparative Example 5.

[0193] Figure 15 is a chromaticity graph for Comparative Example 6.

[0194] The above-mentioned variable transmittance device, etc. will be specifically described through the following examples and comparative examples, but the scope of the above-mentioned variable transmittance device, etc. is not limited by the following examples.

[0195]

[0196] 1. Phase difference evaluation

[0197] The phase difference of the phase difference layer was measured using an Axoscan device (Axomatrix). By scanning the phase difference layer while rotating it within an azimuth range of 0 to 360 degrees using the Axoscan device, the slow axis (n) of the phase difference layer was measured. x ) direction refractive index, fast axis (n y ) refractive index in the ) direction and refractive index in the thickness direction (n z You can check ).

[0198] Through the above measurement results and the following equations 4 to 6, the in-plane phase difference Rin, the thickness direction phase difference Rth, and Nz can be confirmed.

[0199] [Equation 4]

[0200] Rin = (n x -n y ) × d

[0201] [Equation 5]

[0202] Rth = (n z - n y ) × d

[0203] [Equation 6]

[0204] Nz = Rth / Rin

[0205] In Equations 4 to 6, d is the thickness of the phase difference layer.

[0206] The above refractive index was measured for light with a wavelength of 550 nm.

[0207]

[0208] Example 1. Preparation of tint film (A)

[0209] A tint film was manufactured by forming a tint adhesive layer (thickness: about 10 μm) (tint layer) on a PET film (thickness: about 80 μm) (phase difference layer) from Toyobo. The in-plane phase difference Rin of the above SRF film was about 10 μm, and the thickness direction phase difference Rth was about -10 μm (Nz = Rth / Rin = about -1). The above tint layer is a layer in which a tint color is added to an acrylic OCA (Optical Clear Adhesive) such that the transmittance at a wavelength of 550 nm is about 29%, the L* of the CIE 1976 lab* color space is about 25 to 30, and a* and b* are each about 0.

[0210]

[0211] Example 2. Preparation of tint film (B)

[0212] A tint film was prepared in the same manner as in Example 1, except that a PET film from Toyobo (thickness: about 80 μm) (Nz = Rth / Rin = about -0.5) was used, having an in-plane phase difference Rin of about 10 μm and a thickness direction phase difference Rth of about -5 μm.

[0213]

[0214] Example 3. Preparation of tint film (C)

[0215] A tint film was prepared in the same manner as in Example 1, except that a PET film from Toyobo (thickness: about 80 μm) (Nz = Rth / Rin = about -0.75) was used, having an in-plane phase difference Rin of about 10 μm and a thickness direction phase difference Rth of about -7.5 μm.

[0216]

[0217] Comparative Example 1. Preparation of tint film (D)

[0218] A tint film was prepared in the same manner as in Example 1, except that a PET (poly(ethylene terephthalate)) film (thickness: about 80 μm) (Nz = Rth / Rin = about -2) was used, having an in-plane phase difference Rin of about 2.5 μm and a thickness direction phase difference Rth of about -5 μm.

[0219]

[0220] Comparative Example 2. Preparation of tint film (E)

[0221] A tint film was prepared in the same manner as in Example 1, except that a Toyobo SRF film (thickness: about 80 μm) (Nz = Rth / Rin = about -1.25) was used, having an in-plane phase difference Rin of about 10 μm and a thickness direction phase difference Rth of about -12.5 μm.

[0222]

[0223] Comparative Example 3. Preparation of tint film (F)

[0224] A tint film was prepared in the same manner as in Example 1, except that a Toyobo SRF film (thickness: about 80 μm) (Nz = Rth / Rin = about -1.5) was used, which has an in-plane phase difference Rin of about 10 μm and a thickness direction phase difference Rth of about -15 μm.

[0225]

[0226] Example 4

[0227] The material for the polymer-dispersed liquid crystal layer was prepared in the following manner. As the liquid crystal, Bayi's liquid crystal (BHR40568) was used. The liquid crystal is a nematic liquid crystal with a normal refractive index (no) of approximately 1.509 at a wavelength of 550 nm and an abnormal refractive index (ne) of approximately 1.723 at a wavelength of 550 nm. The normal and abnormal refractive indices of the liquid crystal can be evaluated using an Abbe refractometer.

[0228] A PDLC material was prepared by mixing the above liquid crystal and monomer material. The monomer material was prepared by mixing ethylhexyl acrylate (monomer A) (refractive index: approx. 1.436, n20 / D), isobornyl acrylate (monomer B) (refractive index: approx. 1.447, n20 / D), and DEGDA (Di(ethylene glylcol) diacrylate) (monomer C) (refractive index: approx. 1.463, n20 / D) in a weight ratio of 5:4:1 (A:B:C), and then adding an initiator (TPO, CAS No.: 75980-60-8) at a ratio of approximately 3 parts by weight per 100 parts by weight of the mixture. The PDLC material was prepared by mixing the above liquid crystal (L) and the above monomer material (M) in a weight ratio of approximately 55 to 60:45 to 40 (L:M).

[0229] Two substrates were prepared by depositing an ITO (Indium Tin Oxide) layer on one side of the phase difference layer (Toyobo, SRF film, thickness: about 80 μm, Rin: about 10 μm, Rth: about -10 μm, Nz: about -1) of Example 1.

[0230] A transmittance-variable laminate as shown in FIG. 1 was manufactured using the tint film of Example 1 and the prepared PDLC material and substrate.

[0231] The PDLC material is coated on the ITO layer of the substrate (1002), and another substrate (1003) is laminated on the coated PDLC material such that the ITO layer of the substrate is in contact with the PDLC material. Subsequently, at a temperature of approximately 25°C, 0.7 W / cm² 2 A PDLC layer (3000) was formed by irradiating ultraviolet light (wavelength: approximately 365 nm). The PDLC layer (3000) was formed with a thickness of approximately 20 μm. The average size of the droplets in the PDLC layer (3000) was approximately 1.3 μm when confirmed with a Scanning Electron Microscope (SEM).

[0232] Next, as a tint film prepared in Example 1, a tint film including a phase difference layer (1001) and a tint layer (2001) was attached to a substrate (1002), and a tint film including a phase difference layer (1004) and a tint layer (2002) was attached to a substrate (1003) to produce a laminate.

[0233] In the above laminate, the ground axes between the substrate (1002, 1003) and the phase difference layer (1001, 1002) are arranged to be parallel to each other.

[0234]

[0235] Example 5.

[0236] When manufacturing the substrate, the phase difference layer used in Example 2 (Toyobo, SRF film, thickness: about 80 μm, Rin: about 10 μm, Rth: about -5 μm, Nz: about -0.5) was used as the phase difference layer, and the tint film of Example 2 was used instead of the tint film of Example 1 to manufacture the laminate in the same manner as in Example 4.

[0237]

[0238] Example 6.

[0239] When manufacturing the substrate, the phase difference layer used in Example 3 (Toyobo, SRF film, thickness: about 80 μm, Rin: about 10 μm, Rth: about -7.5 μm, Nz: about -0.75) was used as the phase difference layer, and the laminate was manufactured in the same manner as Example 4 by using the tint film of Example 3 instead of the tint film of Example 1.

[0240]

[0241] Comparative Example 4.

[0242] When manufacturing the substrate, the PET (poly(ethylene terephthalate)) film of Comparative Example 1 (PET film, thickness: about 80 μm, Rin: about 2.5 μm, Rth: about -5 μm, Nz: about -2) was used as the phase difference layer, and a laminate was manufactured in the same manner as Example 4 using the tint film of Comparative Example 1 instead of the tint film of Example 1.

[0243]

[0244] Comparative Example 5.

[0245] When manufacturing the substrate, the phase difference layer used in Comparative Example 2 (Toyobo, SRF film, thickness: about 80 μm, Rin: about 10 μm, Rth: about -12.5 μm, Nz: about -1.25) was used as the phase difference layer, and the tint film of Comparative Example 2 was used instead of the tint film of Example 1 to manufacture the laminate in the same manner as Example 4.

[0246]

[0247] Comparative Example 6.

[0248] When manufacturing the substrate, the phase difference layer used in Comparative Example 3 (Toyobo, SRF film, thickness: about 80 μm, Rin: about 10 μm, Rth: about -15 μm, Nz: about -1.5) was used as the phase difference layer, and the laminate was manufactured in the same manner as Example 4 by using the tint film of Comparative Example 3 instead of the tint film of Example 1.

[0249]

[0250] Test Example 1.

[0251] Optical properties were confirmed by irradiating linearly polarized light onto the laminates of the examples and comparative examples. The linearly polarized light was irradiated using a standard light source (Standard Illuminant A, Tungsten Halogen lamp) and a PVA (poly(vinyl alcohol))-based polarizer. Linearly polarized light formed using the standard light source and the PVA-based polarizer was irradiated at a position approximately 90 cm away from the center of gravity of the laminate, which had a width and length of approximately 10 cm each, and optical properties were confirmed on the opposite side of the laminate irradiated with the linearly polarized light.

[0252] FIGS. 5 to 7 are Polar Plots of Examples 4 to 6 obtained by the above method, respectively, and FIGS. 8 to 10 are Polar Plots of Comparative Examples 4 to 6 obtained by the above method, respectively. In each Polar Plot, the azimuth angle is indicated along the circle, and the polar angle is indicated along the x-axis. By comparing the figures, it can be seen that when the polar angle is changed from an azimuth angle of 0 degrees, in the case of the Examples, optical defects such as rainbows do not occur, or if they do occur, they occur at an angle of 70 degrees or more. On the other hand, in the case of Comparative Example 4, they occurred at a small angle of 30 degrees or less, and in the case of Comparative Examples 5 and 6, although they showed somewhat better results compared to Comparative Example 4, it can be seen that severe optical defects occur at an angle of 70 degrees or less.

[0253] FIGS. 11 to 15 are CIE 1931 Chromaticity Diagram graphs of Example 4, Example 5, Example 6, Comparative Example 5, and Comparative Example 6, respectively. Each graph shows the results obtained by verifying color coordinates while varying the polar angle from 0 to 60 degrees at an azimuth angle of 0 degrees in the above tests.

[0254] Spectral data for Figures 11 to 15 were obtained in reflection mode using the HunterLab UltraScan PRO Spectrophotometer and the light source, and the necessary parts for measurement were referenced to ISO 11664-4 standard (10° standard observer conditions).

[0255] From the drawings, it can be seen that in the case of the embodiment, there is almost no change in △E even when the observation angle changes, whereas in the case of Comparative Examples 5 and 6, a significant change in △E is perceived depending on the observation angle.

[0256] △E was calculated from Figures 12 to 16 according to the following Equation 1.

[0257] [Equation 1]

[0258] △E = [(L*-L*') 2 +(a*-a*') 2 +(b*-b*') 2 ] 0.5

[0259] In Equation 1, L* is the L* value of the CIE Lab* color space at an azimuth of 0 degrees and a polar angle of 0 degrees, L*' is the L* value of the CIE Lab* color space at an azimuth of 0 degrees and a polar angle of 60 degrees, a* is the a* value of the CIE Lab* color space at an azimuth of 0 degrees and a polar angle of 0 degrees, a*' is the a* value of the CIE Lab* color space at an azimuth of 0 degrees and a polar angle of 60 degrees, b* is the b* value of the CIE Lab* color space at an azimuth of 0 degrees and a polar angle of 0 degrees, and b*' is the b* value of the CIE Lab* color space at an azimuth of 0 degrees and a polar angle of 60 degrees.

[0260] △E Example 4 114.88 Example 5 124.24 Example 6 134.30 Comparative Example 5 149.28 Comparative Example 6 1525.74

[0261] From the quantification results in Table 1, it can be seen that in the case of the example, there is almost no change in △E even when the observation angle changes, whereas in the case of Comparative Examples 5 and 6, a significant change in △E is perceived depending on the observation angle.

Claims

1. Phase difference layer; and It includes a tint layer formed on one surface of the above-mentioned phase difference layer, and The above phase difference layer has an in-plane phase difference of 3 μm or more for light of a wavelength of 550 nm, and A tint film in which the ratio of the thickness direction phase difference Rth to the in-plane phase difference Rin of the above phase difference layer, Rth / Rin, is -1 or greater.

2. In claim 1, the tint layer is a tint film having a transmittance of 80% or less for a wavelength of 550 nm.

3. In claim 1 or 2, the tint layer is a tint film having an L* of the CIE Lab* color space within the range of 5 to 40.

4. In any one of claims 1 to 3, the tint layer is a tint film in which the a* of the CIE Lab* color space is within the range of -10 to 10.

5. In any one of claims 1 to 4, the tint layer is a tint film in which the b* of the CIE Lab* color space is within the range of -10 to 10.

6. A tint film according to any one of claims 1 to 5, further comprising a second phase difference layer formed on the side of the tint layer where the phase difference layer is not formed, and having an in-plane phase difference of 3 μm or more with respect to light of a wavelength of 550 nm.

7. A tint film according to claim 6, wherein the angle formed by the ground axes of the two phase difference layers is within the range of 0 to 20 degrees or 80 to 100 degrees.

8. A tint film according to any one of claims 1 to 7; and It includes a variable transmittance layer formed on one surface of the above tint film, and The above-mentioned transmittance variable layer is a transmittance variable laminate comprising a polymer and a liquid crystal.

9. A transmittance-variable laminate according to claim 8, wherein △E of the following Equation 1 is 9 or less: [Equation 1] △E = [(L*-L*') 2 +(a*-a*') 2 +(b*-b*') 2 ] 0.5 In Equation 1, L*, a*, and b* are the L*, a*, and b* values ​​of the CIE Lab* color space of the laminate at an azimuth of 0 degrees and a polar angle of 0 degrees, respectively, and L*', a*', and b*' are the L*, a*, and b* values ​​of the CIE Lab* color space of the laminate at an azimuth of 0 degrees and a polar angle of 60 degrees, respectively.

10. In claim 8 or 9, the liquid crystal is a transmittance-variable laminate in which △n of Formula 2 below is within the range of 0.5% to 50%: [Equation 2] △n = 100 × (n e -n o ) / n o n in Equation 2 e is the abnormal refractive index of the above liquid crystal, and n o is the normal refractive index of the liquid crystal.

11. In any one of claims 8 to 10, the polymer is a transmittance-variable laminate comprising a unit of the following chemical formula 1: [Chemical Formula 1] In Chemical Formula 1, R1 is hydrogen or an alkyl group, and R2 is a branched alkyl group.

12. In any one of claims 8 to 11, the polymer is a transmittance-variable laminate comprising a unit of the following chemical formula 2: [Chemical Formula 2] In Chemical Formula 2, R1 is hydrogen or an alkyl group, and R3 is a cycloalkyl group, a bicycloalkyl group, or a tricycloalkyl group.

13. In any one of claims 8 to 12, the polymer is a permeability-variable laminate comprising polymerization units of polyfunctional acrylate.

14. In any one of claims 8 to 13, the total polymerization unit of the polymer is a transmittance-variable laminate having a weight-average refractive index in the range of 1.00 to 1.

7.

15. In any one of claims 8 to 14, the polymer and the liquid crystal are a transmittance-variable laminate in which the absolute value of △R of Formula 3 below is within the range of 0.5% to 50%: [Equation 3] △R = 100 × (n LC -n p ) / n p n in Equation 3 LC is the anomalous refractive index of the liquid crystal based on a wavelength of 550 nm, and n p is the weight-average refractive index of the total polymerization unit of the polymer.

16. An automobile comprising a tint film according to any one of claims 1 to 7 on glass.

17. An automobile comprising a transmittance-variable laminate of any one of claims 8 to 15 in glass.

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