KR102666115B1 - Transmission Variable Device - Google Patents

Abstract

This application relates to an optical modulation device. In this application, while excellent optical properties such as variable transmittance characteristics and mechanical properties, light leakage in all directions is controlled in blocking mode, and appearance defects such as rainbow phenomenon or stretching pattern are controlled, so that it can be applied to various purposes. An optical modulation device can be provided.

Description

Light modulation device {Transmission Variable Device}

This application relates to light modulation devices.

An optical modulation device is a device that can switch between at least two different states. Applying a polymer film substrate to such an optical modulation device makes it easy to implement flexible devices and apply roll-to-roll processes.

At this time, when an isotropic film base material is used as the polymer film, there are problems such as low mechanical strength, occurrence of cracks, or shrinkage due to heat.

However, light modulation devices incorporating an anisotropic film substrate suffer from the problem of deterioration of the driving performance of the device due to the phase difference of the film substrate, for example, light leakage to the side of the light modulation device in blocking mode or rainbow appearance. There is a problem of developing or stretching patterns.

Therefore, in this application, while excellent optical properties such as variable transmittance characteristics and mechanical properties, light leakage in all directions is controlled in blocking mode, and appearance defects such as rainbow phenomenon or stretching pattern are controlled, so that it can be applied to various purposes. One purpose is to provide a possible optical modulation device.

The angles defined in this specification should be understood taking into account errors such as manufacturing errors or variations. For example, the terms vertical, horizontal, perpendicular, parallel or angular in this specification mean substantially vertical, horizontal, perpendicular, parallel or angular in the range that does not impair the intended effect, e.g. , each of the above cases may include an error within approximately ±5 degrees, an error within approximately ±3 degrees, an error within approximately ±2 degrees, an error within approximately ±1 degree, or an error within approximately ±0.5 degrees. .

Among the physical properties mentioned in this specification, in cases where the measurement temperature affects the relevant physical properties, unless otherwise specified, the physical properties are those measured at room temperature.

As used herein, the term room temperature refers to a temperature in a state where the temperature is not particularly heated or reduced, and is any temperature within the range of about 10°C to 30°C, for example, about 15°C or higher, 18°C or higher, 20°C or higher, or about 23°C or higher. It may mean a temperature above ℃ and below about 27℃. Additionally, unless otherwise specified, the unit of temperature referred to in this specification is °C.

In this specification, the in-plane retardation (R _in ) may refer to a value calculated using Equation 4 below, and the thickness direction retardation (R _th ) may refer to a value calculated using Equation 5 below.

[Formula 4]

R _in = d × (n _x - n _y )

[Formula 5]

R _th = d × (n _z - n _y )

In Equations 4 and 5, R _in may be the in-plane phase difference, R _th may be the thickness direction phase difference, d may be the thickness of the layer, n _x may be the refractive index in the slow axis direction of the layer, and n _y is the refractive index in the fast axis direction of the layer, and may be the refractive index in the in-plane direction perpendicular to the slow axis direction, and n _z may be the refractive index in the thickness direction of the layer.

In the above, the term layer refers to a layer subject to measurement of in-plane retardation and/or thickness direction retardation. The layer may be, for example, a polarizing layer, a polymer film, an optically anisotropic layer, or a light modulation layer.

Phase difference, refractive index, refractive index anisotropy, etc. mentioned in this specification are physical quantities for light with a wavelength of about 550 nm, unless otherwise specified.

Unless otherwise specified, the angle formed by any two directions mentioned in this specification may be an acute angle or an obtuse angle formed by the two directions, or may be a smaller angle among angles measured clockwise and counterclockwise. . Accordingly, unless otherwise specified, angles referred to herein are positive numbers. However, in some cases, in order to indicate the measurement direction between angles measured clockwise or counterclockwise, the angle measured in the clockwise direction may be displayed as a positive number, and the angle measured in the counterclockwise direction may be displayed as a negative number.

The light modulation device of the present application may be a device in which a first substrate, a light modulation layer, and a second substrate are formed sequentially. The light modulation device of the present application may include, for example, first and second substrates each having a first surface and a second surface and disposed opposite to each other, and a light modulation layer present between the first and second substrates. You can. For example, in this specification, the first surface refers to one of the main surface of the substrate and the opposite surface, and the second surface may refer to the other surface among the main surface of the substrate and the opposite surface. . In another example herein, the first surface may refer to a direction toward the light modulation layer among the first and second substrates, and the second surface may refer to a direction opposite to the first surface.

In the present application, the first and/or second substrate may each be a polymer film, for example. The polymer film may be isotropic or anisotropic, but it may be preferable to be an anisotropic polymer film from the viewpoint of mechanical strength, crack generation control, or shrinkage control due to heat.

For example, the first and/or second substrate may each have an in-plane retardation of 3000 nm or more for a wavelength of 550 nm. In other examples, the first and/or second polymer films have an in-plane retardation for a wavelength of 550 nm of 3500 nm or more, 4000 nm or more, 4500 nm or more, 5000 nm or more, 5500 nm or more, 6000 nm or more, 6500 nm or more, 7000 nm or more, 7500 nm or more, Above 8000nm or above 8500nm, below 50000nm, below 40000nm, below 30000nm, below 20000nm, below 19000nm, below 18000nm, below 17000nm, below 16000nm, below 15000nm, below 14000nm, below 13000nm, It may be less than or equal to 11000 nm.

Films having a high retardation as described above are known in the industry, and these films exhibit not only high optical anisotropy but also high asymmetry in mechanical properties due to high elongation during the manufacturing process. The retardation film known in the industry includes, for example, polyethylene terephthalate (PET) film, Cyclo-Olefin Polymer (COP) film, and Cyclo-Olefin Co-polymer. ; COC) film, polycarbonate (PC), polypropylene (PP) film, polysulfone (PSF) film, or acrylic (Polymethylmethacrylate (PMMA) film), but is not limited thereto. In the present application, the first and/or second substrate may be appropriately selected from among the known films in consideration of the desired effect, etc.

In the present application, the first and second substrates may be different from each other, for example. The present inventors found that when applying a polymer film having a high phase difference as described above to a first and/or second substrate, the polymer films applied to the first and second substrates must be different from each other to prevent not only the rainbow phenomenon but also the rainbow phenomenon. The present invention was completed after confirming that deterioration in appearance quality, such as stretching patterns, could be improved.

In the present application, the fact that the polymer films applied to the first and second substrates are different from each other may mean, for example, that the in-plane retardation of the first and second substrates is different from each other.

For the first and second substrates of the present application, for example, K in the following equation 1 may be in the range of more than 0 and less than or equal to 0.5.

[Formula 1]

In K in Equation 1, R _in,A is It can mean the in-plane phase difference of the first substrate for light with a wavelength of 550 nm, and R _in,B is It may refer to the in-plane retardation of the second substrate for light with a wavelength of 550 nm, and max(R _in,A , R _in,B ) may refer to the larger value of R _in,A or R _in,B .

In other examples, K in Formula 1 is 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, or 0.09 or more, or 0.45 or less, 0.4 or less, 0.35 or less, 0.3 or less, or 0.25 or more. It may be 0.2 or less or 0.15 or less, but is not limited thereto.

In this application, in K of Equation 1 above, R _{in, A} of The value may be, for example, 6000 nm or more. In other examples, the R _in,A may be 6500 nm or more, 7000 nm or more, 7500 nm or more, 8000 nm or more, or 8500 nm or less, or 12000 nm or less, 11500 nm or less, 11000 nm or less, 10500 nm or less, 10000 nm or less, or 9500 nm or less. It is not limited. Also, in K of Equation 1, R _in,B may be, for example, 8000 nm or more, and in other examples, 8500 nm or more, 9000 nm or more, or 9500 nm, or 15000 nm or less, 14500 nm or less, 14000 nm or less, 13500 nm or less, 13000 nm. Hereinafter, it may be 12500 nm or less, 12000 nm or less, 11500 nm or less, 11000 nm or less, or 10500 nm or less, but is not limited thereto.

The light modulation device of the present application includes, for example, other layers described later, such as a polarization layer and a light modulation layer, by introducing first and second substrates that satisfy Equation 1 and/or Equation 2 described later, respectively. By combining it with other layers, it is possible to control appearance quality degradation such as rainbow phenomenon or stretching pattern.

In the present application, the fact that the polymer films applied to the first and second substrates are different from each other may mean, for example, that the thicknesses of the polymer films are different from each other. In the present application, for example, the first and second substrates may have a P value of 0.3 or more in Equation 2 below.

[Formula 2]

In P in Equation 2, W _A is It may mean the thickness of the first substrate, and W _B is It may refer to the thickness of the second substrate, and min(W _A , W _B ) may refer to the smaller value of W _A or W _B.

In other examples, the value of P in Equation 2 is less than 1, less than 0.95, less than 0.9, less than 0.85, or less than 0.8, or more than 0.35, more than 0.4, more than 0.45, more than 0.5, more than 0.55, more than 0.6, more than 0.65, or more than 0.7. It may be possible, but it is not limited to this.

In the present application, in P of Equation 2, the W _A value may be, for example, in the range of 50㎛ to 100㎛. In other examples, the W _A value may be 55 μm or more, 60 μm or more, 65 μm or more, 70 μm or more, or 75 μm or more, or 95 μm or less, 90 μm or less, or 85 μm or less. In the present application, in P of Equation 2, the W _B value may be, for example, in the range of 120㎛ to 180㎛. In other examples, the W _B value may be 125 ㎛ or more, 130 ㎛ or more, 135 ㎛ or more, or 140 ㎛ or more, or 175 ㎛ or less, 170 ㎛ or less, 165 ㎛ or less, 160 ㎛ or less, 155 ㎛ or less, or 150 ㎛ or less. .

For example, in this application, by introducing first and second substrates that satisfy Equation 1 and/or Equation 2, respectively, optical properties such as variable transmittance characteristics and mechanical properties are excellent, while light leakage in all directions in blocking mode is achieved. It is possible to provide an optical modulation device in which this is controlled and appearance defects such as rainbow phenomenon or stretching pattern are also controlled.

In the present application, the purpose of the present application can be more effectively achieved by introducing polymer films having the above characteristics as the first and second substrates, respectively, and controlling the relationship between the slow axes of the first and second substrates to a predetermined range. there is. For example, the polymer film may be an anisotropic film.

In the present application, the slow axes of the first and second substrates may be arranged to be horizontal to each other, for example. In this specification, the slow axes of the first and second substrates being horizontal to each other means that the slow axes of the first polymer film and the slow axes of the second polymer film are arranged within a range of approximately -10 degrees to 10 degrees. It can mean. In other examples, the slow axes of the first and second polymer films are approximately -9 degrees or greater, approximately -8 degrees or greater, approximately -7 degrees or greater, approximately -6 degrees or greater, approximately -5 degrees or greater, or approximately -4 degrees. or above, approximately -3 degrees or greater, approximately -2 degrees or greater, or approximately -1 degrees or greater, or approximately 9 degrees or lower, approximately 8 degrees or lower, approximately 7 degrees or lower, approximately 6 degrees or lower, approximately 5 degrees or lower, approximately 4 degrees or lower, It may be approximately 3 degrees or less, approximately 2 degrees or less, or approximately 1 degree or less, and may preferably be arranged at 0 degrees.

The present application can provide an optical modulation device in which optical compensation is more effective by additionally introducing an optically anisotropic layer having the characteristics described later along with the first and second substrates having the characteristics described above.

For example, the optically anisotropic layer may be included at least one of between the light modulation layer and the first substrate or between the light modulation layer and the second substrate. In the present specification, it may be included at least one of between the light modulation layer and the first substrate or between the light modulation layer and the second substrate, between the light modulation layer and the first substrate and between the light modulation layer and the second substrate. This means that the optically anisotropic layer is disposed between the second substrates, or between the light modulation layer and the first substrate, or between the light modulation layer and the second substrate. can do.

For example, the optically anisotropic layer may satisfy Equation 3 below.

[Formula 3]

n _z < n _y ≒ n _x

In Equation _{3 , n} It may be the refractive index in the thickness direction of the optically anisotropic layer. In the present specification, A≒B may mean, for example, that the values of A and B are substantially the same, and A and/or B are each, for example, any one of n _x, n _y , or n _z. It can be.

For example, the optically anisotropic layer may have a thickness direction retardation in the range of -50nm to -700nm with respect to light with a wavelength of 550nm. In other examples, the thickness direction phase difference is -60 nm or less, -70 nm or less, -80 nm or less, -90 nm or less, -100 nm or less, -110 nm or less, -120 nm or less, -130 nm or less, -140 nm or less, - Below 150 nm, below -160 nm, below -170 nm, below -180 nm, below -190 nm, below -200 nm, or below -210 nm, or above -690 nm, above -680 nm, above -670 nm, above -660 nm, -650 nm or more, -640 nm or more, -630 nm or more, -620 nm or more, -610 nm or more, -600 nm or more, -590 nm or more, -580 nm or more, -570 nm or more, -560 nm or more, -550 nm or more, -540 nm or more, -530 nm or more, -520 nm or more, -510 nm or more, -500 nm or more, -490 nm or more, -480 nm or more, -470 nm or more, -460 nm or more, -450 nm or more, -440 nm or more, -430 nm or more, -420 nm or more, -410 nm or more, -400 nm or more, -390 nm or more, -380 nm or more, -370 nm or more, -360 nm or more, -350 nm or greater than -340 nm, greater than -330 nm, greater than -320 nm, greater than -310 nm, greater than -300 nm, greater than -290 nm, greater than -280 nm, greater than -270 nm, greater than -260 nm, greater than -250 nm, greater than -240 nm, or greater than -230 nm. there is.

For example, the optically anisotropic layer may have an in-plane retardation of 10 nm or less for light with a wavelength of 550 nm. In another example, the in-plane retardation may be 9 nm or less, 8 nm or less, 7 nm or less, 6 nm or less, 5 nm or less, 4 nm or less, 3 nm or less, 2 nm or less, or 1 nm or less, preferably 0 nm. there is.

In the present application, the optically anisotropic layer can be used without limitation as long as it exhibits the above characteristics. In one example, the optically anisotropic layer can be formed by mixing polyamide with a solvent. In one example, the polyamide can be formed by polymerizing 2,2'-bis(trifluoromethyl)-5,5'-biphenyldiamine with isophthalic acid and/or terephthalic acid. Additionally, the solvent may be dimethylacetamide in one example. The polyamide may be included, for example, in a range of approximately 4% to 10% by weight relative to the solvent, and in other examples, at least 4.5% by weight, at least 5% by weight, or at most 9% by weight, at most 8% by weight. , may be included in 7% by weight or less, 6% by weight or less, or 5.5% by weight or less.

In one example, the solution formed by mixing polyamide in a solvent can be coated by applying it on a polymer film or a conductive layer described later, for example, bar coating method, slot-die coating. method, gravure coating method, etc.

The coating layer formed by the coating may be hardened by heat curing or ultraviolet curing. In one example, the optically anisotropic layer of the present application may be a layer formed by curing the coating layer by applying heat in the range of approximately 50°C to 150°C for a time in the range of approximately 5 minutes to 30 minutes. In another example, the curing temperature may be 60°C or higher, 70°C or higher, 80°C or higher, or 90°C or lower, or 140°C or lower, 130°C or lower, 120°C or lower, or 110°C or lower, and the curing time may be 6 minutes or higher, It may be 7 minutes or more, 8 minutes or more, or 9 minutes or less, or 25 minutes or less, 20 minutes or less, or 15 minutes or less, but is not limited thereto.

For example, the optically anisotropic layer may have a refractive index anisotropy (n△) in the range of 0.01 to 0.15. In other examples, the refractive index anisotropy (n△) may be 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, or 0.09 or more, or 0.14 or less, 0.13 or less, 0.12 or less, or 0.11 or less.

The optically anisotropic layer may also have an average refractive index in the range of 1.0 to 2.0, for example. In other examples, the average refractive index may be 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, or 1.6 or more, or 1.9 or less, 1.8 or less, or 1.7 or less.

In the present application, the optically anisotropic layer may have a thickness in the range of, for example, 0.1㎛ to 10㎛. In other examples, the thickness is greater than or equal to about 0.2 μm, greater than or equal to about 0.3 μm, greater than or equal to about 0.4 μm, greater than or equal to about 0.5 μm, greater than or equal to about 0.6 μm, greater than or equal to about 0.7 μm, greater than or equal to about 0.8 μm, greater than or equal to about 0.9 μm, or greater than or equal to about 1 μm. or more, about 1.1 ㎛ or more, about 1.2 ㎛ or more, about 1.3 ㎛ or more, about 1.4 ㎛ or more, about 1.5 ㎛ or more, about 1.6 ㎛ or more, about 1.7 ㎛ or more, about 1.8 ㎛ or more, or about 1.9 ㎛ or more, or about 9 ㎛. Hereinafter, it may be about 8 μm or less, about 7 μm or less, about 6 μm or less, about 5 μm or less, about 4 μm or less, or about 3 μm or less.

The present application controls light leakage to the side in blocking mode by additionally including an optically anisotropic layer having the above characteristics at an appropriate position of the light modulation device, while compensating for it by the optical properties of the first and second polymer films. This can solve the problem of distorted effects.

The present application may further include, for example, a polarizing layer formed on one or more surfaces of the first and/or second surfaces of the second substrate. In the present application, the polarizing layer may be formed only on the second surface of the first substrate, only on the second surface of the second substrate, or may be formed on both the second surfaces of the first and second substrates, but in blocking mode In terms of controlling light leakage, it may preferably be formed on both the second surfaces of the first and second substrates.

In this specification, a polarizing layer may refer to a device that changes natural light or non-polarized light into polarized light. For example, the polarizing layer may be a linear polarizing layer. In this specification, a linear polarization layer refers to a case where the selectively transmitted light is linearly polarized light vibrating in one direction, and the light selectively absorbed or reflected is linearly polarized light vibrating in a direction perpendicular to the vibration direction of the linearly polarized light. That is, the linear polarizer may have a transmission axis and an absorption axis or reflection axis that are orthogonal to the plane direction.

The polarizing layer may be an absorbing polarizing layer or a reflective polarizing layer. The absorbing polarizing layer includes, for example, a polarizing layer dyed with iodine on a stretched polymer film such as PVA (in this specification, PVA refers to polyvinyl alcohol) stretched film, or a liquid crystal polymerized in an aligned state as a host. In addition, a guest-host type polarizing layer using an anisotropic dye arranged according to the orientation of the liquid crystal as a guest may be used, but is not limited thereto. As the reflective polarizing layer, for example, a reflective polarizing layer known as DBEF (Dual Brightness Enhancement Film) or a reflective polarizing layer formed by coating a liquid crystal compound such as LLC (Lyotropic liquid crystal) may be used. However, it is not limited to this.

In the present application, the polarizing layer may have a thickness ranging from, for example, 80 μm to 200 μm. In another example, the thickness of the polarizing layer is 90 ㎛ or more, 100 ㎛ or more, 110 ㎛ or more, 120 ㎛ or more, or 130 ㎛ or less, or 190 ㎛ or less, 180 ㎛ or less, 170 ㎛ or less, 160 ㎛ or less, or 150 ㎛ or less. You can.

For example, the light modulation device of the present application is arranged so that the first surfaces of the first and second substrates face each other, and includes a liquid crystal compound between the opposingly arranged first and second substrates. It may include a modulation layer.

In the present application, the light modulation layer is a layer containing at least a liquid crystal compound, and may refer to a liquid crystal layer in which the alignment state of the liquid crystal compound can be controlled through the application of an external signal, etc.

The liquid crystal compound may be, for example, a nematic liquid crystal compound, a smectic liquid crystal compound, or a cholesteric liquid crystal compound. In addition, for example, it may be a compound that does not have a polymerizable group or a crosslinkable group, or it may have a compound that is not polymerized or crosslinked so that its orientation direction can be changed by the application of an external signal.

For example, the light modulation layer may include a liquid crystal compound having negative dielectric anisotropy, or the light modulation layer may exhibit the above-mentioned dielectric anisotropy. The absolute value of dielectric anisotropy may be appropriately selected considering the purpose of the present application. The term “permittivity anisotropy (△ε)” may mean the difference (ε// -ε⊥) between the horizontal permittivity (ε//) and the vertical permittivity (ε⊥). In this specification, the term horizontal dielectric constant (ε//) refers to a dielectric constant value measured along the direction of the electric field while applying a voltage so that the direction of the electric field due to the director of the liquid crystal molecules and the applied voltage is substantially horizontal, The vertical dielectric constant (ε⊥) refers to a dielectric constant value measured along the direction of the electric field while applying a voltage such that the direction of the electric field caused by the applied voltage is substantially perpendicular to the director of the liquid crystal molecules.

For example, the light modulation layer may include a liquid crystal compound having a refractive index anisotropy (nΔ) in the range of about 0.04 to 0.15, or the light modulation layer may exhibit the above-mentioned refractive index anisotropy. The refractive index anisotropy (n△) of the present application may be the difference (ne-no) between the abnormal refractive index (ne, extraordinary refractive index) and the normal refractive index (no, ordinary refractive index). In the present specification, ne may be, for example, n _z , and no may be, for example, n _x and/or n _y . That is, in the present application, the refractive index anisotropy (n△) may be, for example, n _z -n _x or n _z -n _y . In other examples, the refractive index anisotropy (nΔ) may be about 0.14 or less, 0.13 or less, 0.12 or less, 0.11 or less, or 0.1 or less, or 0.05 or more, 0.06 or more, or 0.07 or more.

The light modulation layer may also have an average refractive index in the range of 1.0 to 2.0, for example. The average refractive index of the present application may mean the average value ((ne+no)/2) of the abnormal refractive index (ne) and the normal refractive index (no). In this specification, the average refractive index may be, for example, (n _x +n _z )/2 or (n _y +n _z )/2. In other examples, the average refractive index may be 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, or 1.5 or more, or 1.9 or less, 1.8 or less, 1.7 or less, or 1.6 or less.

The driving modes of the optical modulation layer include, for example, Reversed TN (Twisted Nematic) mode, Reversed STN (Super Twisted Nematic) mode, VA (Vertical Alignment) mode, MVA (Multi-domain Vertical Alignment) mode, and PVA (Patterned Nematic) mode. It may be Vertical Alignment) mode, HAN (Hybrid Aligned Nematic) mode, etc.

The light modulation layer of the present application may further include a dichroic dye together with the liquid crystal compound in terms of controlling the variable light transmittance characteristics. In this specification, the term “dye” may refer to a material that can intensively absorb and/or modify light within at least part or the entire range of visible light, for example, within the 400 nm to 700 nm wavelength range, and the term “ “Dichroic dye” may refer to a material capable of anisotropic absorption of light in at least part or the entire range of the visible light region. Examples of such dyes include known azo dyes and anthraquinone dyes, but are not limited thereto.

In one example, the light modulation layer is a liquid crystal layer containing a liquid crystal compound and a dichroic dye, and may be a so-called guest host liquid crystal cell. The term “GHLC layer” refers to a functional layer in which dichroic dyes are arranged together according to the arrangement of the liquid crystal and exhibit anisotropic light absorption characteristics with respect to the alignment direction of the dichroic dye and the direction perpendicular to the alignment direction. . For example, a dichroic dye is a material whose light absorption rate varies depending on the polarization direction. If the absorption rate of light polarized in the major axis direction is high, it is called a p-type dye. If the absorption rate of light polarized in the minor axis direction is high, it is called an n-type dye. It can be called. In one example, when a p-type dye is used, polarized light vibrating in the long axis direction of the dye is absorbed, and polarized light vibrating in the short axis direction of the dye has low absorption and can be transmitted.

The ratio of the dichroic dye included in the guest host liquid crystal layer is not particularly limited and can be set to an appropriate range considering the desired transmittance. In general, considering the miscibility of the dichroic dye and the liquid crystal compound, the dichroic dye may be included in the light modulation layer at a ratio of about 0.1% to 4% by weight.

This application, for example, adjusts the arrangement of the liquid crystal compound in the light modulation layer, so that the initial alignment is vertical, and the vertical alignment state is designed to be changed to the horizontal alignment state by application of an external signal. It may be about the device. Additionally, the horizontal orientation may be a twisted orientation. In the above, initial orientation refers to an orientation state when no external signal is applied to the optical modulation layer. As used herein, the term vertical alignment refers to a state in which the director of the light modulation layer or the director of the liquid crystal compound in the light modulation layer is arranged approximately perpendicular to the plane of the light modulation layer, for example, the light modulation layer The angle formed by the z-axis, which is the normal line of the reference plane, and the director may be in the range of about 80 degrees to 100 degrees, 85 degrees to 95 degrees, or about 90 degrees. In addition, the term horizontal orientation may mean a state in which the director of the light modulation layer or the director of the liquid crystal compound in the light modulation layer is arranged approximately parallel to the reference plane of the light modulation layer, for example, in the direction. The angle formed between the ruler and the reference plane of the light modulation layer may be in the range of about 0 degrees to 10 degrees, about 0 degrees to 5 degrees, or about 0 degrees.

In this specification, the term director of the light modulation layer or the director of the liquid crystal compound may mean the optical axis or slow axis of the light modulation layer. For example, the optical axis or slow axis may mean the long axis direction if the liquid crystal molecule is rod-shaped, and may mean the axis in the normal direction of the disc plane if the liquid crystal molecule is disc-shaped, When a plurality of liquid crystal compounds having different directors are included in the light modulation layer, it may mean the vector sum of the directors of the liquid crystal compounds.

This application, for example, adjusts the arrangement of the liquid crystal compound in the light modulation layer, so that the initial alignment is vertical, and the vertical alignment state is designed to be changed to the horizontal alignment state by application of an external signal. It may be about the device. In the above, initial orientation refers to an orientation state when no external signal is applied to the optical modulation layer, that is, in blocking mode.

For example, the light modulation layer may be designed to implement a twist orientation mode. As used herein, the term twist alignment mode may refer to a helical structure in which the directors of the liquid crystal compounds are oriented in layers while twisting along a virtual helical axis.

In one example, the twist alignment mode can be implemented in a horizontal alignment mode, and in the case of a vertical alignment mode, the director of the light modulation layer or the director of the liquid crystal compound in the light modulation layer is the light modulation layer without twisting. It may be arranged approximately perpendicular to the plane. The horizontal twist alignment mode may mean, for example, a state in which individual liquid crystal compounds are horizontally aligned and twisted along a spiral axis to form a layer.

In the horizontal twist orientation mode, the ratio (d/p) between the thickness (d, cell gap) and the pitch (p) of the light modulation layer may be, for example, 1 or less. If the ratio (d/p) exceeds 1, the liquid crystal compounds may be twisted along the helical axis even in the initial vertical alignment mode, and problems such as finger domains may occur, so it is preferably within the above range. can be adjusted. In other examples, the ratio (d/p) is about 0.95 or less, about 0.9 or less, about 0.85 or less, about 0.8 or less, about 0.75 or less, about 0.7 or less, about 0.65 or less, about 0.6 or less, about 0.55 or less, about 0.5 or less. Alternatively, it may be about 0.45 or less, about 0.1 or more, about 1.15 or more, about 0.2 or more, about 0.25 or more, about 0.3 or more, or about 0.35 or more. In the above, the thickness (d) of the light modulation layer may have the same meaning as the cell gap in the light modulation device.

The pitch (p) of the optical modulation layer in the horizontal twist orientation mode can be measured by a measurement method using a wedge cell, and specifically, the Simple method for accurate measurements of the cholesteric pitch using a stripe-wedge Grandjean by D. Podolskyy et al. -It can be measured by the method described in Cano cell (Liquid Crystals, Vol. 35, No. 7, July 8\2008, 789-791).

The light modulation layer may further include a so-called chiral dopant so that the light modulation layer can implement a horizontal twist mode.

Chiral dopant that may be included in the light modulation layer may be used without particular limitation as long as it can induce the desired twisting without damaging liquid crystallinity, for example, nematic regularity. . A chiral dopant for inducing rotation in liquid crystal molecules needs to include at least chirality in its molecular structure. Chiral dopants are, for example, compounds with one or more asymmetric carbons, compounds with asymmetric points on heteroatoms such as chiral amines or chiral sulfoxides, or cumulene. ) or a compound having an optically active site (axially asymmetric, optically active site) with an axial agent such as binaphthol may be exemplified. For example, the chiral dopant may be a low molecular weight compound with a molecular weight of 1,500 or less. As the chiral dopant, a commercially available chiral nematic liquid crystal, for example, chiral dopant liquid crystal S811 available from Merck or LC756 from BASF, etc. may be applied.

The application ratio of the chiral dopant is not particularly limited as long as the desired ratio (d/p) can be achieved. In general, the content (% by weight) of the chiral dopant is calculated by the formula 100/(HTP (Helixcal Twisting power) × Pitch (nm), and can be selected at an appropriate ratio considering the desired pitch (p). One In an example, the chiral dopant may be included such that the pitch (p) is in the range of approximately 5㎛ to 50㎛, and in another example, the chiral dopant may have a pitch of approximately 6㎛ or more, 7㎛ or more, or 8㎛. or more, 9㎛ or more, 10㎛ or more, 11㎛ or more, 12㎛ or more, 13㎛ or more, 14㎛ or more, 15㎛ or more, 16㎛ or more, 17㎛ or more, 18㎛ or more, or 19㎛ or more, or 45㎛ or less, The appropriate range is 40 ㎛ or less, 35 ㎛ or less, 30 ㎛ or less, 29 ㎛ or less, 28 ㎛ or less, 27 ㎛ or less, 26 ㎛ or less, 25 ㎛ or less, 24 ㎛ or less, 23 ㎛ or less, 22 ㎛ or less or 21 ㎛. may be included.

The thickness of the light modulation layer of the present application may be appropriately selected in consideration of the purpose of the present application. In one example, the thickness of the light modulation layer may be about 15㎛ or less. By controlling the thickness in this way, it is possible to implement a device with a large difference in transmittance between transmission mode and blocking mode, that is, a device with excellent transmittance variable characteristics. In other examples, the thickness is about 14㎛ or less, 13㎛ or less, 12㎛ or less, 11㎛ or less, 10㎛ or less, 9㎛ or less, 8㎛ or less, or 7㎛ or less, or 1㎛ or more, 2㎛ or more, or 3㎛. It may be more than 4㎛, or more than 4㎛, or more than 5㎛, but is not limited thereto.

In this application, by introducing the above-mentioned light modulation layer at an appropriate position along with the above-described polymer film and/or optically anisotropic layer, etc., the transmittance variable characteristics and mechanical properties are excellent, and omnidirectional light leakage in the blocking mode is controlled while It is possible to provide an optical modulation device that can control appearance quality degradation such as rainbow phenomenon or stretching pattern.

For example, the light modulation device of the present application may have an adhesive layer or adhesive layer formed thereon. For example, the adhesive layer or pressure-sensitive adhesive layer may include an adhesive or pressure-sensitive adhesive having a vertical alignment force. As used herein, the term adhesive or pressure-sensitive adhesive having a vertical alignment force may refer to a material that has both a vertical alignment force and an adhesive force (or adhesive force) to liquid crystal molecules.

For example, the adhesive or pressure-sensitive adhesive having the vertical alignment force may be formed on at least one surface of one surface of the first substrate and/or one surface of the second substrate. In one example, an adhesive or pressure-sensitive adhesive having a vertical alignment force may be present on the first surface of the first substrate, and a liquid crystal alignment film may be formed on the first surface of the second substrate.

In the present application, for example, a silicone adhesive or a silicone adhesive may be used as an adhesive or adhesive having a vertical alignment force. The silicone adhesive or silicone pressure-sensitive adhesive may be a cured product of a composition containing a curable silicone compound. The type of the curable silicone compound is not particularly limited, and for example, a heat-curable silicone compound or an ultraviolet curable silicone compound can be used.

In one example, the curable silicone composition is an addition curable silicone composition, which includes (1) an organopolysiloxane containing two or more alkenyl groups in the molecule and (2) an organopolysiloxane containing two or more silicon-bonded hydrogen atoms in the molecule. may include. The above silicone compound can form a cured product through an addition reaction in the presence of a catalyst such as a platinum catalyst, for example.

The organopolysiloxane (1) above is a main component constituting the cured silicone product, and contains at least two alkenyl groups in one molecule. At this time, specific examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, or a heptenyl group. Among these, the vinyl group is usually applied, but is not limited thereto. In the above (1) organopolysiloxane, the bonding position of the above-mentioned alkenyl group is not particularly limited. For example, the alkenyl group may be bonded to the terminal of the molecular chain and/or to the side chain of the molecular chain. In addition, in the organopolysiloxane (1), types of substituents that may be included in addition to the alkenyl group described above include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, or heptyl group; Aryl groups such as phenyl group, tolyl group, xylyl group, or naphthyl group; Aralkyl groups such as benzyl group or penentyl group; Halogen-substituted alkyl groups such as chloromethyl group, 3-chloropropyl group, or 3,3,3-trifluoropropyl group are included, and among these, methyl group or phenyl group are usually applied, but are not limited thereto.

The molecular structure of the organopolysiloxane (1) above is not particularly limited, and may have any shape, such as straight chain, branched, ring, network, or partially branched straight chain. Usually, among the above molecular structures, those having a linear molecular structure are particularly applied, but are not limited thereto.

More specific examples of the above (1) organopolysiloxane include, dimethylsiloxane-methylvinylsiloxane copolymer, blocking trimethylsiloxane groups at both ends of the molecular chain, methylvinylpolysiloxane, blocking trimethylsiloxane groups at both ends of the molecular chain, and blocking trimethylsiloxane groups at both ends of the molecular chain. Dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer, blocking the dimethylvinylsiloxane groups at both ends of the molecular chain. Dimethylpolysiloxane, blocking the dimethylvinylsiloxane groups at both ends of the molecular chain. Methylvinylpolysiloxane, blocking the dimethylvinylsiloxane groups at both ends of the molecular chain. Dimethylsiloxane-methyl. Vinylsiloxane copolymer, dimethylvinylsiloxane group blocked at both ends of the molecular chain Dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer, siloxane unit expressed as R ¹ ₂ SiO _2/2 and R ¹ ₂ R ² SiO _1/2 Organopolysiloxane copolymer containing a siloxane unit and a siloxane unit represented by SiO _4/2 , an organopolysiloxane copolymer containing a siloxane unit represented by R ¹ ₂ R ² SiO _1/2 and a siloxane unit represented by SiO _4/2 Organopolysiloxane copolymer, an organopolysiloxane copolymer comprising a siloxane unit represented by R ¹ R ² SiO _2/2 and a siloxane unit represented by R ¹ SiO _3/2 or a siloxane unit represented by R ² SiO _3/2 and mixtures of two or more of the above, but are not limited thereto. In the above, R ¹ is a hydrocarbon group other than an alkenyl group, and specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or a heptyl group; Aryl groups such as phenyl group, tolyl group, xylyl group, or naphthyl group; Aralkyl groups such as benzyl group or penentyl group; It may be a halogen-substituted alkyl group such as a chloromethyl group, 3-chloropropyl group, or 3,3,3-trifluoropropyl group. In addition, in the above, R ² is an alkenyl group, and may specifically be a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, or a heptenyl group.

In the addition-curable silicone composition, (2) organopolysiloxane may serve to crosslink (1) organopolysiloxane. In the above (2) organopolysiloxane, the bonding position of the hydrogen atom is not particularly limited, and for example, it may be bonded to the terminal and/or side chain of the molecular chain. In addition, in the (2) organopolysiloxane, the types of substituents that may be included in addition to the silicon bond hydrogen atom are not particularly limited, for example, as mentioned in (1) organopolysiloxane, an alkyl group, an aryl group, Examples include an aralkyl group or a halogen-substituted alkyl group, and among these, a methyl group or a phenyl group is usually applied, but is not limited thereto.

The molecular structure of the organopolysiloxane (2) is not particularly limited, and may have any shape, such as straight chain, branched, ring, network, or partially branched straight chain. Among the molecular structures described above, those having a linear molecular structure are generally applied, but are not limited thereto.

More specific examples of the above (2) organopolysiloxane include methylhydrogenpolysiloxane with trimethylsiloxane groups blocked at both ends of the molecular chain, dimethylsiloxane-methylhydrogen copolymer with blocked trimethylsiloxane groups at both ends of the molecular chain, and trimethylsiloxane groups at both molecular chain ends. Blocked dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymer, dimethylpolysiloxane with blocked dimethylhydrogensiloxane groups at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer with blocked dimethylhydrogensiloxane groups at both ends of the molecular chain, dimethyl both ends of the molecular chain Hydrogensiloxane group-blocked methylphenylpolysiloxane, an organopolysiloxane aerial comprising siloxane units represented by R ¹ ₃ SiO _1/2 and siloxane units represented by R ¹ ₂ HSiO _1/2 and siloxane units represented by SiO _4/2 polymer, an organopolysiloxane copolymer comprising a siloxane unit represented by R12HSiO1/2 and a siloxane unit represented by SiO _4/2 , a siloxane unit represented by R ¹ HSiO _2/2 and a siloxane unit represented by R ¹ SiO _3/2 Examples include, but are not limited to, organopolysiloxane copolymers containing siloxane units or siloxane units represented by HSiO _3/2 and mixtures of two or more of the above. In the above, R ¹ is a hydrocarbon group other than an alkenyl group, and specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or a heptyl group; Aryl groups such as phenyl group, tolyl group, xylyl group, or naphthyl group; Aralkyl groups such as benzyl group or penentyl group; It may be a halogen-substituted alkyl group such as a chloromethyl group, 3-chloropropyl group, or 3,3,3-trifluoropropyl group.

The content of the organopolysiloxane (2) above is not particularly limited as long as it is contained in an amount that allows appropriate curing. For example, the (2) organopolysiloxane may be included in an amount of 0.5 to 10 silicon-bonded hydrogen atoms per alkenyl group included in the above-mentioned (1) organopolysiloxane. Within this range, hardening can sufficiently proceed and heat resistance can be secured.

The addition-curable silicone composition may further include platinum or a platinum compound as a catalyst for curing. As such, the specific type of platinum or platinum compound is not particularly limited. The ratio of catalyst can also be adjusted to a level where appropriate curing can be achieved.

The addition-curable silicone composition may also contain appropriate additives in an appropriate ratio from the viewpoint of improving storage stability, handling, and workability.

In another example, the silicone composition is a condensation-curable silicone composition, for example, (a) an alkoxy group-containing siloxane polymer; and (b) a hydroxyl group-containing siloxane polymer.

The (a) siloxane polymer may be, for example, a compound represented by the following formula (1).

[Formula 1]

R ¹ _a R ² _b SiO _c (OR ³ ) _d

In Formula 1, R ¹ and R ² each independently represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R ³ represents an alkyl group, and when multiple R ¹ , R ² and R ³ each exist, They may be the same or different from each other, and a and b each independently represent a number greater than 0 and less than 1, a+b represents a number greater than 0 and less than 2, and c represents a number greater than 0 and less than 2. , d represents a number greater than 0 and less than 4, and a+b+c×2+d is 4.

In the definition of Formula 1, the monovalent hydrocarbon may be, for example, an alkyl group having 1 to 8 carbon atoms, a phenyl group, a benzyl group, or a tolyl group, and in this case, the alkyl group having 1 to 8 carbon atoms includes a methyl group, an ethyl group, a propyl group, It may be an isopropyl group, butyl group, pentyl group, hexyl group, heptyl group, or octyl group. In addition, in the definition of Formula 1, the monovalent hydrocarbon group may be substituted with a known substituent such as, for example, halogen, amino, mercapto, isocyanate, glycidyl, glycidoxy, or ureido.

In the definition of Formula 1, examples of the alkyl group of R ³ include methyl group, ethyl group, propyl group, isopropyl group, or butyl group. Among alkyl groups, methyl groups or ethyl groups are commonly used, but are not limited thereto.

Among the polymers of Formula 1, branched or tertiary crosslinked siloxane polymers can be used. Additionally, hydroxyl groups may remain in this (a) siloxane polymer within a range that does not impair the purpose, and specifically, within a range that does not inhibit the dealcoholization reaction.

The (a) siloxane polymer can be produced, for example, by hydrolyzing and condensing polyfunctional alkoxysilane or polyfunctional chlorosilane. An average skilled person in this field can easily select an appropriate polyfunctional alkoxysilane or chlorosilane depending on the desired (a) siloxane polymer, and can also easily control the conditions for hydrolysis and condensation reactions using it. On the other hand, when producing the siloxane polymer (a), an appropriate monofunctional alkoxy silane may be used in combination depending on the purpose.

Examples of the (a) siloxane polymer include commercially available organosiloxanes such as X40-9220 or Polymers can be used.

As the hydroxyl group-containing siloxane polymer (b) contained in the condensation-curable silicone composition, for example, a compound represented by the following formula (2) can be used.

[Formula 2]

In Formula 2, R ⁴ and R ⁵ each independently represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, and when multiple R ⁵ and R ⁶ exist, they may be the same or different from each other. and n represents an integer from 5 to 2,000.

In the definition of Formula 2, specific types of monovalent hydrocarbon groups include, for example, the same hydrocarbon groups as those in Formula 1 above.

The (b) siloxane polymer can be produced, for example, by hydrolyzing and condensing dialkoxysilane and/or dichlorosilane. An average person skilled in the field can easily select an appropriate dialkoxy silane or dichlorosilane depending on the desired (b) siloxane polymer, and can also easily control the conditions of hydrolysis and condensation reactions using it. As the (b) siloxane polymer as described above, for example, commercially available bifunctional organosiloxane polymers such as XC96-723, YF-3800, and YF-3804 from GE Toray Silicone Co., Ltd. can be used.

The addition-curable or condensation-curable silicone composition described above is an example of a material for forming the silicone adhesive or adhesive applied in the present application. That is, basically all silicone adhesives or adhesives known in the industry as OCA or OCR can be applied in the present application.

The type of the adhesive or adhesive or the curable composition forming it is not particularly limited and may be appropriately selected depending on the intended use. For example, a solid, semi-solid or liquid adhesive or adhesive or curable composition may be used. A solid or semi-solid adhesive or adhesive or curable composition may be cured before the adhesive (or adhesive) object is bonded. The liquid adhesive or adhesive or curable composition is called optical clear resin (OCR), and can be cured after the adhesive or adhesive object is bonded. According to one example, the adhesive or adhesive or curable composition is a so-called polydimethyl siloxane-based adhesive or adhesive or curable composition or a polymethylvinyl siloxane-based adhesive or adhesive or curable composition or an alkoxy Alkoxy silicone-based adhesives, adhesives, or curable compositions may be used, but are not limited thereto.

The thickness of the adhesive layer or adhesive layer is not particularly limited and may be selected within an appropriate range to secure the desired adhesion or adhesion. The thickness may range from approximately 1㎛ to 50㎛. In other examples, the thickness is 2㎛ or more, 3㎛ or more, 4㎛ or more, 5㎛ or more, 6㎛ or more, 7㎛ or more, 8㎛ or more, or 9㎛ or more, or 45㎛ or less, 40㎛ or less, or 35㎛ or less. , it may be about 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less.

Under the above arrangement, by including the above adhesive layer or adhesive layer, it is possible to apply a roll-to-roll process, which provides excellent fairness, excellent adhesion (or adhesion), and especially light in blocking mode. It is possible to provide an optical modulation device that can exhibit excellent optical properties by controlling leakage.

In this way, when the liquid crystal compound is vertically aligned by the alignment of the liquid crystal compound formed by a known vertical alignment film and an adhesive or adhesive having vertical alignment ability, or by the combination of the above-mentioned retardation film and/or optical anisotropic layer, etc., omnidirectional side light is generated. Leakage can be effectively suppressed, and absorption of front light can be minimized during horizontal orientation.

In the present application, for example, a liquid crystal alignment film may be formed on the first surface of the second substrate. The liquid crystal alignment layer may be used to determine the initial orientation of the light modulation layer. The type of liquid crystal alignment layer applied at this time is not particularly limited, and may be, for example, a known rubbing alignment layer or a photo-alignment layer.

The alignment direction of the liquid crystal alignment layer may be a rubbing direction in the case of a rubbing alignment layer, or the direction of irradiated polarized light in the case of a photo-alignment layer. This alignment direction can be confirmed by a detection method using a linear polarizer. For example, when the light modulation layer is in a twisted orientation mode such as Reversed TN (Twisted Nematic) mode, a linear polarizer is placed on one side, and the transmittance is measured while changing the absorption axis of the polarizer, the absorption axis or the transmission axis and the liquid crystal When the orientation directions of the alignment films match, the transmittance tends to be low, and the orientation direction can be confirmed through simulation reflecting the refractive index anisotropy of the applied liquid crystal compound. A method of confirming the alignment direction of the liquid crystal alignment layer according to the mode of the light modulation layer is known. Additionally, as described above, the liquid crystal alignment layer may be a known rubbing alignment layer or a photo-alignment layer, and the type of alignment layer that can be applied depending on the desired mode is known.

In the present application, the thickness of the liquid crystal alignment layer may be, for example, in the range of 50 nm to 1000 nm. In other examples, the thickness of the liquid crystal alignment film is 60 nm or more, 70 nm or more, 80 nm or more, or 90 nm or less, or 9000 nm or less, 8000 nm or less, 7000 nm or less, 6000 nm or less, 5000 nm or less, 4000 nm or less, and 3000 nm or less. , 2000 nm or less, 1000 nm or less, 900 nm or less, 800 nm or less, 700 nm or less, 600 nm or less, 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, 190 nm or less, 180 nm or less, 170 It may be less than 160 nm, less than 150 nm, less than 140 nm, less than 130 nm, less than 120 nm, or less than 110 nm.

In one example of the present application, when an adhesive layer or pressure-sensitive adhesive layer having a vertical alignment force as described above is formed on one surface of the first substrate, a liquid crystal alignment layer may not be formed on the first substrate. Through this configuration, it is possible to apply it to a roll-to-roll process and ensure excellent fairness.

In the present application, the gap between the first and second substrates arranged opposite each other may be maintained by a spacer in the form of a partition. In one example, as shown in Figure 1, a first polarizing layer 101/first substrate 201/optically anisotropic layer 700/adhesive layer or adhesive layer 400/light modulation layer 300/liquid crystal alignment film ( 500)/second substrate 202/second polarization layer 102 may be sequentially formed, and the gap G between the first and second substrates may be maintained by the partition-shaped spacer 800. . At this time, the light modulation layer 300 may exist in a region where the spacer 800 does not exist, but is not limited thereto.

In the present application, the shape and arrangement method of the spacer can be appropriately designed within a range that allows, for example, to maintain a constant gap between the second substrate and the first substrate.

The spacer of the present application may exist to form a partition in the shape of a partition, or may exist in the shape of two or more pillars spaced apart, but is not limited thereto. In one example, the spacer may be in the shape of a square, triangle, or honeycomb partition. In terms of effectively controlling light leakage in the blocking mode, a square partition shape may be appropriate, and a square or rectangular partition shape may be appropriate, but is not limited thereto.

In the present application, the arrangement method of the spacer, for example, pitch, line width, height, and area ratio on the upper or second substrate, etc. may be appropriately selected within a range that does not impair the purpose of the present application. In the above, the area ratio refers to the percentage of the area where the spacer is formed compared to the total area of the first surface of the second substrate.

In this specification, the term pitch refers to the spacing between opposing sides or the spacing between opposing vertices and sides as seen when the spacer is observed from above. In this specification, observing the spacer from above means observing the spacer parallel to the normal direction of the surface of the polymer film substrate formed with the spacer. In one example, when the spacer is in the shape of a triangular partition, the term pitch may mean the vertical distance between one vertex of the triangle and the side facing the vertex. In another example, in the case of a square partition shape, the term pitch may refer to the length of each side of the square, and if the lengths of each side of the square are the same (i.e., if the angle is a square), the length of the same sides is the pitch. It is defined as, and when the lengths of each side are not the same (for example, when a square is a rectangle), the arithmetic average of the lengths of all sides can be defined as the pitch. In another example, when the spacer is in the shape of a honeycomb (in the case of a hexagon) partition, the term pitch may mean the spacing of opposing sides of the hexagon, and if the spacing of the opposing sides are all the same, the spacing of the same sides The length of is defined as the pitch, and if the spacing of each side is not the same, the arithmetic average of the lengths of the spacing of all sides may be defined as the pitch.

In the present application, the pitch of the spacer may be, for example, 50㎛ to 1000㎛, and in other examples, it is 100㎛ or more, 150㎛ or more, 200㎛ or more, 250㎛ or more, or 300㎛ or more, or 950㎛ or less, or 900㎛. Hereinafter, it may be 850 μm or less, 800 μm or less, 750 μm or less, 700 μm or less, 650 μm or less, 600 μm or less, 550 μm or less, 600 μm or less, 450 μm or less, or 400 μm or less.

In this specification, the term line width refers to a dimension confirmed in a direction perpendicular to the longitudinal direction of the partition when the spacer is observed from above. The line width of the spacer may be, for example, 1㎛ to 50㎛, and in other examples, 2㎛ or more, 3㎛ or more, 4㎛ or more, 5㎛ or more, 6㎛ or more, 7㎛ or more, 8㎛ or more, or 9㎛ or more. ㎛ or less, 45㎛ or less, 40㎛ or less, 35㎛ or less, 30㎛ or less, 25㎛ or less, 20㎛ or less, 19㎛ or less, 18㎛ or less, 17㎛ or less, 16㎛ or less, 15㎛ or less, 14㎛ or less , may be 13 μm or less, 12 μm or less, or 11 μm or less.

In addition, the term spacer height generally roughly corresponds to the thickness (cell gap) of the light modulation layer and refers to the spacer dimension measured in the normal direction of the surface of the above-mentioned polymer film substrate. In the present application, the height of the spacer can be adjusted considering the gap between the first and second substrates. For example, the height of the spacer may be 1 ㎛ to 20 ㎛, and in other examples, 2 ㎛ or more, 3 ㎛ or more, 4 ㎛ or more, or 5 ㎛ or more, or 19 ㎛ or less, 18 ㎛ or less, 17 ㎛ or less, 16 It may be ㎛ or less, 15 ㎛ or less, 14 ㎛ or less, 13 ㎛ or less, 12 ㎛ or less, 11 ㎛ or less, 10 ㎛ or less, 9 ㎛ or less, 8 ㎛ or less, or 7 ㎛ or less. In one example, the height of the spacer may be approximately equal to the thickness of the light modulation layer.

In this specification, the term area ratio refers to the ratio of the area where the spacer is formed (B) to the area (A) of the polymer film substrate, assuming that the area of the polymer film substrate is A and the area where the spacer is formed is B. The value is multiplied by 100. , That means 100×B/A. In the present application, the area ratio of the spacer may be about 0.1% to 50% with respect to the first or second polymer film substrate. In the present application, as the area ratio of the spacer increases, the adhesion (or adhesive force) of the first and second polymer film substrates may increase. In other examples, it is greater than 1%, greater than 2%, greater than 3%, greater than 4%, greater than 5%, greater than 6%, greater than 7%, or greater than 8%, or greater than 45%, greater than 40%, greater than 35%, or greater than 30%. It may be % or less, 25% or less, 20% or less, 15% or less, or 10% or less.

In the present application, the spacer may include, for example, a curable resin. The curable resin may be, for example, a heat-curable resin or a photo-curable resin, for example, an ultraviolet curable resin, but is not limited thereto. The heat-curable resin may be, for example, silicone resin, silicon resin, phran resin, polyurethane resin, epoxy resin, amino resin, phenol resin, urea resin, polyester resin, or melamine resin, but is not limited thereto. The UV curable resin is typically an acrylic polymer, such as polyester acrylate polymer, polystyrene acrylate polymer, epoxy acrylate polymer, polyurethane acrylate polymer, polybutadiene acrylate polymer, silicone acrylate polymer, or alkyl acrylate. Polymers, etc. may be used, but are not limited thereto. In one example, the spacer may be formed using an acrylic polymer, more specifically, a polyester-based acrylate polymer, but is not limited thereto, and in another example, it may be formed using a silicone polymer. When the spacer is formed using a silicone polymer, the silicone polymer remaining in the concave area of the spacer may serve as a vertical alignment layer, so an additional liquid crystal alignment layer may not be used on the substrate on which the spacer is present, as described above. As the silicone polymer, for example, a known polymer mainly based on the bond between silicon and oxygen (Si-O-Si), for example, polydimethylsiloxane (PDMS), can be used, but is not limited thereto.

The present application provides a light modulation device in which the cell gap is appropriately maintained, the adhesion (or adhesion) of the upper and lower film substrates is excellent, and light leakage in blocking mode is also appropriately controlled by controlling the shape and/or arrangement method of the spacer as described above. can be provided.

In one example, the light modulation device of the present application has a transmittance of 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% when in blocking mode. or less, 20% or less, 15% or less, 10% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, It may be 0.5% or less, 0.4% or less, or 0.3% or less. Since lower transmittance is more advantageous in blocking mode, the lower limit of the transmittance in the blocking mode state is not particularly limited. In one example, the lower limit of the transmittance in the blocking mode state may be about 0%.

In one example, the light modulation device of the present application may have a transmittance of 20% or more in a transmission mode, and in another example, it may have a transmittance of 21% or more, 22% or more, 23% or more, or 24% or more. The upper limit of the transmittance in the transmission mode state is not particularly limited, but in one example, the upper limit of the transmittance in the transmission mode state may be 60%, and in another example, 55% or less, 50% or less, 45% or less, It may be around 40% or less, 35% or less, or 30% or less.

In one example, the light modulation device of the present application has a transmittance difference between the transmission mode and the blocking mode of 15% or more, 16% or more, 17% or more, 18% or more, 19% or more, 20% or more, It can be 21% or more, 22% or more, 23% or more, or 24% or more, or 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, It may be 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, or 25% or less.

The transmittance may be, for example, straight light transmittance. The straight light transmittance may be a percentage of the ratio of light transmitted in the same direction as the incident direction with respect to the light incident on the light modulation device. For example, if the device is in the form of a film or sheet, the percentage of light that has transmitted through the device in a direction parallel to the normal direction among the light incident in a direction parallel to the z-axis direction, which is the normal direction of the surface of the film or sheet, is calculated as It can be defined as transmittance.

The transmittance is the transmittance or reflectance for any wavelength within the visible light region, for example, about 400 nm to 700 nm or about 380 nm to 780 nm, the transmittance or reflectance for the entire visible light region, or the transmittance or reflectance for the entire visible light region. Among transmittances and reflectances, it may be the maximum or minimum transmittance or reflectance, or it may be the average value of the transmittance or reflectance within the visible light region. Additionally, in another example, the transmittance may be the transmittance for light with a wavelength of about 550 nm.

In one example, the light modulation device of the present application may have a tilt angle transmittance of 3% or less when in a blocking mode. In this specification, the tilt angle transmittance refers to the z-axis direction, which is the normal direction of the reference surface of the measurement object (for example, it may be the surface of a polarizing layer, polymer film, retardation film, optical anisotropic layer, or light modulation layer of a light modulation device). The transmittance of light passing through the object to be measured parallel to the direction of the axis whose inclination angle is Θ may be a value measured while varying the inclination angle Φ. In one example, the z-axis direction, which is the normal direction of the reference surface of the measurement object, is set as 0 degrees, and the east inclination angle Φ in FIG. 7 with respect to 60 degrees (inclination angle Θ in FIG. 7) is 0 degrees, 45 degrees, 90 degrees, 135 degrees, It may mean the transmittance measured while varying at 180 degrees, 225 degrees, 270 degrees, and 315 degrees. In the present application, the tilt angle transmittance in the blocking mode may be, in other examples, 2.9% or less, 2.8% or less, or 2.7% or less, or 0% or more, 0.5% or more, 1% or more, 1.5% or more, or 2% or more. , but is not limited to this.

For example, the light modulation device of the present application may further include a conductive layer on one surface of each of the first and second substrates. For example, a conductive layer may be formed between the adhesive layer or the adhesive layer and the first substrate, and between the liquid crystal alignment layer and the second substrate.

When a conductive layer is formed, the optically anisotropic layer is disposed between the first substrate and the conductive layer or between the conductive layer and an adhesive layer or adhesive layer, and/or between the second substrate and the conductive layer or between the conductive layer. It may be disposed between the layer and the liquid crystal alignment layer.

The conductive layer can transfer an appropriate electric field to the light modulation layer to change the alignment state of the liquid crystal compound in the light modulation layer. The direction of the electric field may be vertical or horizontal, for example, the thickness direction or surface direction of the light modulation layer.

The conductive layer may be, for example, a transparent conductive layer, and the transparent conductive layer may be formed by depositing, for example, a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as ITO (Indium Tin Oxide). there is. In addition, various materials and forming methods that can form a transparent conductive layer are known, and can be applied without limitation.

The optical modulation device described above can be applied to various purposes. Applications to which light modulation devices can be applied include openings in closed spaces including buildings, containers, or vehicles, such as windows or sunroofs, eyewear, etc., windows, and light shields for OLEDs (organic light emitting devices). etc. may be exemplified. The scope of eyewear in the above includes all eyewear designed to allow the observer to observe the outside through a lens, such as general glasses, sunglasses, sports goggles, helmets, or wearable devices such as virtual reality or augmented reality experience devices. You can.

A representative application to which the light modulation device of the present application can be applied may include a sunroof for a vehicle.

In one example, the light modulation device may itself be a sunroof for a vehicle. For example, in an automobile including a car body in which at least one opening is formed, the light modulation device or a vehicle sunroof may be mounted on the opening.

A sunroof is a fixed or operating (venting or sliding) opening in the ceiling of a vehicle, which can refer to a device that allows light or fresh air to enter the interior of the vehicle. there is. In the present application, the operating method of the sunroof is not particularly limited, and for example, it may be operated manually or driven by a motor, and the shape, size, or style of the sunroof may be appropriately selected depending on the intended use. For example, depending on how the sunroof operates, there are three types: pop-up type sunroof, spoiler (tile & slide) type sunroof, inbuilt type sunroof, folding type sunroof, top-mounted type sunroof, and panoramic sunroof. Examples may include, but are not limited to, a roof system type sunroof, a removable roof panel (t-tops or targa roofts) type sunroof, or a solar type sunroof.

The exemplary sunroof of the present application may include the light modulation device of the present application, and in this case, the specific details of the light modulation device may be equally applied to those described in the section on the light modulation device.

This application relates to a light modulation device. In this application, while excellent optical properties such as variable transmittance characteristics and mechanical properties, light leakage in all directions is controlled in blocking mode, and appearance defects such as rainbow phenomenon or stretching pattern are controlled, so that it can be applied to various purposes. An optical modulation device can be provided.

1 is a schematic diagram of an exemplary light modulation device of the present application.
Figure 2 is a diagram showing a method for evaluating refractive index anisotropy.
Figure 3 shows the results of testing the presence or absence of rainbow phenomenon for the light modulation device of Example 1.
Figure 4 shows the results of testing the presence or absence of rainbow phenomenon for the light modulation device of Comparative Example 1.
Figure 5 shows the results of testing the presence or absence of rainbow phenomenon for the light modulation device of Comparative Example 2.

The present application will be described in detail through examples below, but the scope of the present application is not limited by the examples below.

Evaluation example 1. Appearance quality test

To determine whether a rainbow phenomenon or stretching pattern occurs, place an orthogonal polarizer on a back-light unit, place the light modulation device of Examples and Comparative Examples on the orthogonal polarizer, and visually inspect it from the side. observed.

Evaluation example 2. Transmittance measurement in blocking mode

Transmittance in blocking mode (no voltage applied, 0V) was measured using a haze meter (NDH5000SP, Secos) according to the ASTM D1003 standard.

Specifically, when light with a wavelength of 380 nm to 780 nm is incident on the measurement object in the integrating sphere, the incident light is divided into diffuse light (DT, the sum of all light diffused and emitted) and straight light (PT, excluding the diffuse light) depending on the measurement object. (light exiting in the front direction). The diffused light and the straight light can be measured by concentrating them on a light-receiving element within an integrating sphere. That is, through the above process, the total transmitted light (TT) can be defined as the sum (DT+PT) of the diffused light (DT) and straight light (PT). The total transmitted light refers to the total transmittance.

Evaluation example 3. In-plane phase difference evaluation

The in-plane retardation (Rin) of polymer films, etc. was measured using Agilent's UV/VIS spectroscope 8453 equipment (based on a wavelength of 550 nm). Install two polarizers on a UV/VIS spectroscope so that their transmission axes are orthogonal to each other, place a polymer film, etc. between the two polarizers so that their slow axes are at 45 degrees with the transmission axes of the two polarizers, and then The transmittance was measured. The phase retardation order of each peak was obtained from the transmittance graph according to wavelength. Specifically, in the transmittance graph according to wavelength, the waveform satisfies Equation A below, and the maximum peak (Tmax) condition in the sine waveform satisfies Equation B below. In the case of λmax in formula A, T in formula A and T in formula B are the same, so expand the formula. If the equations are developed for n+1, n+2, and n+3, the n and n+1 equations are organized to eliminate R, and n is organized into the λn and λn+1 equations, the following equation C is derived. Since n and λ can be known based on the fact that T in formula A and T in formula B are the same, R is obtained for each λn, λn+1, λn+2, and λn+3. For the 4 points, obtain a straight trend line of the R value according to the wavelength and calculate the R value for light with a wavelength of 550 nm. The function of a straight trend line is Y=ax+b, where a and b are constants. The Y value when 550 nm is substituted for x in the above function is the Rin value for light with a wavelength of 550 nm.

[Formula A]

T = sin2[(2πR/λ)]

[Formula B]

T = sin2[((2n+1)π/2)]

[Formula C]

n = (λn -3λn+1)/(2λn+1 +1-2λn)

In the above, R refers to the in-plane phase difference (Rin), λ refers to the wavelength, and n refers to the peak order of the sinusoidal waveform.

Evaluation Example 4. Thickness of each layer

The thickness of the light modulation layer matched the height of the spacer, and the height of the spacer was confirmed using a measuring device (Optical profiler, Nano system, Nano View-E1000). In addition, the thickness of the optically anisotropic layer was confirmed using the measuring equipment (Optical profiler, Nano system, Nano View-E1000).

Meanwhile, the thickness of the polarizing layer, retardation film, and adhesive layer (or adhesive layer) was measured using a Digimatic Thickness Gauge (547, Mitutoyo Co., Ltd.).

Evaluation Example 5. Evaluation of refractive index anisotropy and average refractive index of light modulation layer (liquid crystal layer) or optically anisotropic layer

The refractive index anisotropy (△n) and average refractive index of the light modulation layer or optically anisotropic layer are evaluated using an Abbe refractometer in the following manner. When a vertical alignment film is coated on the surfaces of the measuring prism and illumination prism of an Abbe refractometer, and the object to be measured is applied to the measuring prism and then covered with the illumination prism, the vertical alignment force of the two interfaces causes the light modulation layer, retardation film, or optical The anisotropic layer is vertically oriented. At this time, the liquid crystal compound applied to the light modulation layer in the above process is only a liquid crystal compound that is not mixed with other substances such as dichroic dye.

Then, as shown in Figure 2, when a linear polarizer is applied to the eyepiece side (grounded part) and light is irradiated and observed, θ _e and θ _o as shown in Figure 2 can be obtained, and measuring prism Through the refractive index (n _p ) and the angles (θ _e and θ _o ), the abnormal refractive index (n _e = n _p sinθ _e ) and the normal refractive index (n _o = n _p sinθ _o ) can be obtained. Here, the difference (n _e -n _o ) can be defined as refractive index anisotropy, and the average value ((n _e + n _o )/2) can be defined as the average refractive index. . The reference wavelength during the above measurement is approximately 550 nm.

Example 1.

A device was manufactured using stretched PET (polyethylene terephthalate) film (SKC) with a thickness of 80 ㎛ and 145 ㎛ as the first and second substrates, respectively. The first substrate had an in-plane retardation of approximately 9,000 nm for light with a wavelength of 550 nm, and the in-plane retardation of the second substrate for light with a wavelength of 550 nm was approximately 10,000 nm.

After bar-coating the -C plate material on one side of the first substrate, it was cured at about 130°C for 20 minutes to form an optically anisotropic layer with a thickness of about 2㎛, and then ITO (Indium Tin Oxide) was applied on the optically anisotropic layer. ) A film (conductive layer) was deposited. The thickness direction retardation of the optically anisotropic layer for light with a wavelength of 550 nm was approximately -220 nm, the refractive index anisotropy was approximately 0.1, and the average refractive index was 1.65. Here, the -C plate material is a polyamide polymerized with terephthalic acid, isophthalic acid, and 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine at approximately 5.3% by weight based on the dimethylacetamide solution. It was prepared by mixing.

Next, a silicone adhesive (KR3700, Shinetsu Co., Ltd.) having a vertical orientation was bar-coated on the ITO film and cured at about 150°C for 10 minutes to form an adhesive layer about 10㎛ thick (first polymer film substrate ).

First, an ITO (Indium Tin Oxide) film (conductive layer) is deposited on one side of the second substrate, and a spacer in the form of a square partition (pitch: 350㎛, height: 350㎛) is placed on the ITO film to maintain the cell gap. 6㎛, line width: 10㎛, area ratio: 9%) was formed. Afterwards, to control the initial orientation of the light modulation layer (liquid crystal layer), a polyimide-based vertical alignment film (SE-5661LB3, Nissan) with a thickness of approximately 100 nm was formed and then subjected to rubbing treatment with a rubbing cloth. At this time, the rubbing direction was perpendicular to the slow axes of the first and second substrates (second polymer film substrate).

Next, the adhesive layer of the first polymer film substrate was placed so that the vertical alignment layer of the second polymer film substrate faced each other (Cell gap: 6㎛), and a liquid crystal material was injected into it, and then a device was manufactured through a lamination process. . The liquid crystal material includes a liquid crystal compound (MAT-19-1261, Merck) with a negative dielectric anisotropy with a refractive index anisotropy (Δn) of approximately 0.07 and an average refractive index of approximately 1.58, and a chiral dopant (S811, Merck). A composition combining the following was used. At this time, the chiral dopant was mixed in an amount of about 0.58 parts by weight based on 100 parts by weight of the liquid crystal compound, so that the chiral pitch was approximately 20㎛.

Next, a first polarizing layer was attached to the side of the first substrate on which the optically anisotropic layer was not formed, and a second polarizing layer was attached to the side of the second substrate on which the ITO film (conductive layer) was not formed. A general PVA polarizing layer was used as the first and second polarizing layers, and each had a thickness of 140 μm.

During the arrangement, the slow axes of the first and second substrates are horizontal to each other, the absorption axes of the first and second polarizing layers are perpendicular to each other, and the absorption axes of the first polarizing layer are aligned with the first and second polymer films. It was placed horizontal to the ground axis. In addition, the rubbing direction of the vertical alignment layer and the slow axis of the second polymer film were arranged to be perpendicular to each other.

As a result, light modulation having the structure of first polarizing layer/first substrate/-C plate/ITO film/adhesive layer/light modulation layer (liquid crystal layer)/vertical alignment film/ITO film/second substrate/second polarizing layer. The device has been formed.

As a result of performing an external quality test on the optical modulation device formed in Example 1, it was confirmed that there was no rainbow phenomenon or stretching pattern, which is shown in FIG. 3.

Comparative Example 1.

As the first and second substrates, the same stretched PET (Polyethylene terephthalate) film (SKC) was used, each with a thickness of 145㎛ and an in-plane retardation of about 10,000nm for light with a wavelength of 550nm. It was prepared in the same way as Example 1.

As a result of performing an appearance quality test on the optical modulation device formed in Comparative Example 1, a rainbow phenomenon and stretching pattern were observed, which are shown in FIG. 4.

Comparative Example 2.

As the first and second substrates, the same stretched PET (Polyethylene terephthalate) film (SKC) was used, each having a thickness of 80㎛ and an in-plane retardation of about 9,000nm for light with a wavelength of 550nm. It was prepared in the same way as Example 1.

As a result of performing an appearance quality test on the optical modulation device formed in Comparative Example 2, a rainbow phenomenon and stretching pattern were observed, which are shown in FIG. 5.

101, 102: first and second polarizing layers
201, 202: first and second substrates
400: Adhesive layer or adhesive layer
500: liquid crystal alignment film
300: Light modulation layer
800: Spacer
700: Optically anisotropic layer
G: cell gap

Claims (17)

first and second substrates each having a first surface and a second surface and disposed opposite to each other; and
It includes a light modulation layer present between the first and second substrates,
An optical modulation device in which K in Equation 1 below is in the range of more than 0 and less than or equal to 0.5:
[Formula 1]

In K in Equation 1, R _in,A is Means the in-plane retardation of the first substrate for light with a wavelength of 550 nm, and R _in,B is Means the in-plane retardation of the second substrate for light of 550 nm wavelength, max(R _in,A , R _in,B ) means the larger value of R _in,A or R _in,B , and the in-plane retardation is a value calculated using Equation 4 below:
[Formula 4]
R _in = d × (n _x - n _y )
In Equation 4, R _in is the in-plane retardation, d is the thickness of the first or second substrate, n _x is the refractive index of the first or second substrate in the slow axis direction, and n _y is the first It is the refractive index of the substrate or the second substrate in the direction of the fast axis. The light modulation device of claim 1, wherein the first and second substrates have an in-plane retardation of 3000 nm or more for light with a wavelength of 550 nm. The light modulation device of claim 1, wherein the first and second substrates have a P value of 0.3 or more in Equation 2 below:
[Formula 2]

In P in Equation 2, W _A is means the thickness of the first substrate, and W _B is It means the thickness of the second substrate, and min(W _A , W _B ) means the smaller value of W _A or W _B. The method of claim 1, wherein an adhesive layer or adhesive layer is formed on the first surface of the first substrate, and a liquid crystal alignment film is formed on the first surface of the second substrate, and the first and second substrates are adjacent to each other. 1 A light modulation device arranged with opposing surfaces. The light modulation device according to claim 4, wherein the adhesive layer or adhesive layer is a silicone adhesive layer or a silicone adhesive layer. The light modulation device according to claim 4, wherein no liquid crystal alignment layer is formed on the first substrate. The light modulation device of claim 4, wherein the liquid crystal alignment layer is a vertical alignment layer. The light modulation device of claim 1, comprising an optically anisotropic layer at least one of the light modulation layer and the first substrate or the light modulation layer and the second substrate. 2. The light modulating device of claim 1, further comprising a polarizing layer formed on at least one of the first surface or the second surface of the second substrate. The light modulation device of claim 1, wherein the first and second substrates are each an anisotropic film, and the slow axes of the first and second substrates are horizontal to each other. The light modulation device according to claim 1, wherein the gap between the first and second substrates is maintained by a partition-shaped spacer. 12. The light modulation device of claim 11, wherein the spacer is square, triangular or honeycomb partition shaped. The light modulation device of claim 1, wherein the light modulation layer includes a liquid crystal compound. The light modulation device according to claim 1, wherein the light modulation layer is formed to be capable of switching between a vertical alignment mode and a horizontal twisted mode. The light modulation device according to claim 14, wherein the light modulation layer is formed so that a vertical alignment mode is implemented in the initial state. The light modulation device according to claim 14, wherein a ratio d/p between the thickness d of the light modulation layer and the pitch p of the twisted mode is 1 or less.
The light modulation device of claim 1, wherein the first and second substrates have different thicknesses.