KR102675896B1 - Method for manufacturing optical device and optical device - Google Patents

Abstract

This application relates to a method of manufacturing an optical device and an optical device. The optical device of the present application can be used for various purposes, such as eyewear such as sunglasses or eyewear for AR (Argumented Reality) or VR (Virtual Reality), the exterior wall of a building, or a sunroof for a vehicle.

Description

Method for manufacturing optical device and optical device}

This application relates to optical devices and methods of manufacturing optical devices.

Various optical devices designed to vary transmittance using liquid crystal compounds are known.

For example, a transmittance variable device using the so-called GH (Guest host) method is known, which applies a mixture of a host material, which is mainly a liquid crystal compound, and a dichroic dye guest, and in the device, the host material is used as the host material. Liquid crystal compounds are mainly used. These transmittance variable devices are applied to a variety of applications, including general display devices such as TVs and monitors, eyewear such as sunglasses and glasses, exterior walls of buildings, and sunroofs of vehicles.

This application provides a method of manufacturing an optical device and an optical device. A possible method of encapsulating an optical device such as a light modulation film is to apply an encapsulating agent such as an adhesive film between at least two outer substrates.

However, the outer substrate is usually rigid, and in comparison, the optical device is flexible. Additionally, in encapsulation, heat and pressure are generally applied to optical devices, etc. Therefore, in the above encapsulation process, waves or wrinkles are easily generated in the internal structure of the encapsulation, such as an optical device, due to the applied heat and pressure.

Accordingly, one purpose of the present application is to provide a method of manufacturing an optical device that can solve the above problems and an optical device manufactured by the method.

Hereinafter, the present application will be described in detail with reference to the attached drawings. The attached drawings illustrate exemplary embodiments of the present application and are provided to aid understanding of the present application. In the attached drawings, the thickness may be enlarged to clearly express each layer and area, and the scope of the present application is not limited by the thickness, size, and ratio shown in the drawings.

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

In this specification, the term room temperature refers to a natural temperature that is not heated or reduced, and may generally be any temperature in the range of about 10°C to 30°C, about 23°C, or about 25°C.

In this specification, the term normal pressure refers to natural pressure that has not been particularly reduced or increased, and generally refers to a pressure of about 1 atmosphere, which is the same as atmospheric pressure.

This application relates to a method of manufacturing an optical device, and specifically, to a method of manufacturing an optical device having a structure in which the optical device is encapsulated with an encapsulating agent within two outer substrates.

Additionally, this application may be directed to an optical device obtained according to the method described above.

The optical device may be an optical device capable of adjusting transmittance, for example, an optical device capable of switching between at least a transmission mode and a blocking mode.

As used herein, the term transmission mode refers to a transmittance of about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, about 35% or more, about 40% or more, about 45% or more, or about 50% or more. It may mean a state of more than %. Additionally, the blocking mode may mean a state in which the transmittance is about 20% or less, about 15% or less, about 10% or less, or about 5% or less. Since the transmittance in the transmission mode is more advantageous as the value is higher, and the transmittance in the blocking mode is more advantageous as the value is lower, the upper and lower limits of each are not particularly limited. In one example, the upper limit of the transmittance in the transmission mode may be about 100%, about 95%, about 90%, about 85%, about 80%, about 75%, about 70%, about 65%, or about 60%. . The lower limit of the transmittance in the blocking mode is about 0%, about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9% or about It could be 10%.

The transmittance may be straight light transmittance. The term straight light transmittance may be a ratio of light (straight light) transmitted through the optical device in the same direction as the incident direction to light incident on the optical device in a predetermined direction. In one example, the transmittance may be a result of measuring light incident in a direction parallel to the surface normal of the optical device (normal light transmittance).

Light whose transmittance is adjusted in an optical device may be ultraviolet rays, visible light, or near-infrared rays in the UV-A region. According to commonly used definitions, ultraviolet light in the UV-A region is used to mean radiation with a wavelength within the range of 320 nm to 380 nm, and visible light is used to refer to radiation with a wavelength within the range of 380 nm to 780 nm. Near-infrared rays are used to mean radiation with a wavelength in the range of 780 nm to 2000 nm.

To provide the optical device, the encapsulated optical device may be a light modulation film or a polarizing layer, or both of the above depending on the case.

1 is a diagram showing an exemplary light modulation film of the present application. Referring to FIG. 1, the light modulation film of the present application is a first base film 110 and a second base film 150 arranged opposite each other, and the light existing between the first and second base films 110 and 150. It may include a modulation layer 130. First and second electrode layers 120 and 140 may be formed on opposite sides of the first and second base films 110 and 150, respectively.

As the base film, for example, an inorganic film or plastic film made of glass or the like can be used. Plastic films include TAC (triacetyl cellulose) film; COP (cyclo olefin copolymer) films such as norbornene derivatives; Acrylic films such as PMMA (poly(methyl methacrylate)); PC (polycarbonate) film; PE (polyethylene) film; PP (polypropylene) film; PVA (polyvinyl alcohol) film; DAC (diacetyl cellulose) film; Pac (polyacrylate) film; PES (polyetheretherketone) film, PPS (polyetherimide) film, PET (polyethyleneterephtalate) film; PSF (polysulfone) film; A PAR (polyarylate) film or a fluororesin film may be used, but the base film is not limited to this and, if necessary, a coating layer of a silicon compound such as gold, silver, silicon dioxide, or silicon monoxide, or a coating layer such as an anti-reflection layer. This may exist.

As the base film, a film having a phase difference within a predetermined range can be used. In one example, the base film may have a front retardation of 100 nm or less. In other examples, the front phase difference is about 95 nm or less, about 90 nm or less, about 85 nm or less, about 80 nm or less, about 75 nm or less, about 70 nm or less, about 65 nm or less, about 60 nm or less, about 55 nm or less. or less, about 50 nm or less, about 45 nm or less, about 40 nm or less, about 35 nm or less, about 30 nm or less, about 25 nm or less, about 20 nm or less, about 15 nm or less, about 10 nm or less, about 5 nm or less Or less, it may be about 4 nm or less, about 3 nm or less, about 2 nm or less, about 1 nm or less, or about 0.5 nm or less. In other examples, the front phase difference is about 0 nm or more, about 1 nm or more, about 2 nm or more, about 3 nm or more, about 4 nm or more, about 5 nm or more, about 6 nm or more, about 7 nm or more, about 8 nm. It may be greater than or equal to about 9 nm, or greater than or equal to about 9.5 nm.

The absolute value of the thickness direction retardation of the base film may be, for example, 200 nm or less. In other examples, the absolute value of the thickness direction retardation is 190 nm or less, 180 nm or less, 170 nm or less, 160 nm or less, 150 nm or less, 140 nm or less, 130 nm or less, 120 nm or less, 110 nm or less, 100 nm or less. , 90 nm or less, 85 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, 10 nm or less, 5 nm or less, 4 nm or less, 3 It may be less than or equal to 2 nm, less than or equal to 1 nm or less than or equal to 0.5 nm, and greater than or equal to 0 nm, greater than or equal to 10 nm, greater than or equal to 20 nm, greater than or equal to 30 nm, greater than or equal to 40 nm, greater than or equal to 50 nm, greater than or equal to 60 nm, greater than or equal to 70 nm or greater than or equal to 75 nm. It may be more than nm. The thickness direction phase difference may be a negative number or a positive number if its absolute value is within the above range, for example, it may be a negative number.

In this specification, the term “front phase difference (Rin)” is a value calculated using the following general formula 1, and the term “thickness direction retardation (Rth)” is a value calculated using the following general formula 2, unless otherwise specified. , the reference wavelength of the front and thickness direction retardation is about 550 nm.

[General Formula 1]

Front phase difference (Rin) = d × (nx - ny)

[General Formula 2]

Thickness direction phase difference (Rth) = d × (nz - ny)

In General Formulas 1 and 2, d is the thickness of the base film, nx is the refractive index in the slow axis direction of the base film, ny is the refractive index in the fast axis direction of the base film, and nz is the refractive index in the thickness direction of the base film.

When the base film is optically anisotropic, the angle formed by the slow axes of the opposing base films is, for example, within the range of about -10 degrees to 10 degrees, within the range of -7 degrees to 7 degrees, and -5 degrees to 5 degrees. It may be within a range of degrees or within a range of -3 degrees to 3 degrees or may be approximately parallel. In addition, the angle formed between the slow axis of the base film and the light absorption axis of the polarizing layer described later is, for example, within the range of about -10 degrees to 10 degrees, within the range of -7 degrees to 7 degrees, and -5 degrees to 5 degrees. degrees, or within the range of -3 degrees to 3 degrees, or may be approximately parallel, or within the range of about 80 degrees to 100 degrees, within the range of about 83 degrees to 97 degrees, within the range of about 85 degrees to 95 degrees, or within the range of about 87 degrees. to 92 degrees or may be approximately vertical.

Through the phase difference adjustment or arrangement of the slow axis as described above, it may be possible to implement optically excellent and uniform transmission and blocking modes.

The base film may have a thermal expansion coefficient of 100 ppm/K or less. The thermal expansion coefficient is, in other examples, 95 ppm/K or less, 90 ppm/K or less, 85 ppm/K or less, 80 ppm/K or less, 75 ppm/K or less, 70 ppm/K or less, or 65 ppm/K or less. , 10 ppm/K or more, 20 ppm/K or more, 30 ppm/K or more, 40 ppm/K or more, 50 ppm/K or more, or 55 ppm/K or more. The thermal expansion coefficient of the base film can be measured, for example, according to the provisions of ASTM D696, and the thermal expansion coefficient can be calculated by cutting the film into the shape provided by the standard and measuring the change in length per unit temperature. It can be measured using a known method such as TMA (ThermoMechanic Analysis).

As the base film, a base film with an elongation at break of 90% or more can be used. The elongation at break is 95% or more, 100% or more, 105% or more, 110% or more, 115% or more, 120% or more, 125% or more, 130% or more, 135% or more, 140% or more, 145% or more, 150% or more. It can be 155% or more, 160% or more, 165% or more, 170% or more, or 175% or more, and 1,000% or less, 900% or less, 800% or less, 700% or less, 600% or less, 500% or less, 400% or less. It may be less than, 300% or less, or less than 200%. The breaking elongation of the base film can be measured according to the ASTM D882 standard, and the film is cut into the shape provided by the standard and equipment that can measure the stress-strain curve (capable of measuring force and length simultaneously) is used. It can be measured using

A more durable optical device can be provided by selecting the base film to have the above coefficient of thermal expansion and/or elongation at break.

The thickness of the base film in the light modulation film is not particularly limited and may typically range from about 50 ㎛ to 200 ㎛.

In this specification, the first base film on which the first electrode layer is formed may be referred to as a first electrode base film, and the second base film on which the second electrode layer is formed may be referred to as a second electrode base film.

The electrode base film may have light transparency, for example, in the visible light region. In one example, the electrode base film may have a transmittance of at least 80%, at least 85%, or at least 90% for light in the visible light region, for example, at any wavelength within the range of about 400 nm to 700 nm or at a wavelength of 550 nm. . The higher the value of the transmittance, the more advantageous, and the upper limit is not particularly limited. For example, the transmittance may be about 100% or less or less than 100%.

The material of the electrode layer formed on the electrode base film is not particularly limited, and any material applicable to forming an electrode layer in the optical device field can be used without particular limitation.

For example, the electrode layer includes metal oxide; metal wire; metal nanotubes; metal mesh; carbon nanotubes; graphene; Alternatively, an electrode layer formed using a conductive polymer or a composite material thereof may be applied.

In one example, the electrode layer includes antimony (Sb), barium (Ba), gallium (Ga), germanium (Ge), hafnium (Hf), indium (In), lanthanum (La), magnesium (Mg), Selected from the group consisting of selenium (Se), aluminum (Al), silicon (Si), tantalum (Ta), titanium (Ti), vanadium (V), yttrium (Y), zinc (Zn), and zirconium (Zr). A metal oxide layer containing one or more metals may be used.

The thickness of the electrode layer can be appropriately selected within a range that does not impair the purpose of the present application. Typically, the thickness of the electrode layer may be in the range of 50 nm to 300 nm or 70 nm to 200 nm, but is not limited thereto. The electrode layer may have a single-layer structure made of the above-mentioned materials, or may have a laminated structure. In the case of a laminated structure, the materials constituting each layer may be the same or different.

The electrode base film can be obtained by forming the electrode layer on the first and second base films.

The light modulation film may include a light modulation layer between the first and second base films on which the electrode layers are respectively formed (that is, at least between the electrode layers). In one example, this light modulation layer may be an active liquid crystal layer containing at least a liquid crystal compound. The term active liquid crystal layer is a layer containing a liquid crystal compound and may refer to a layer that can change the orientation state of the liquid crystal compound through external energy. Using the active liquid crystal layer, an optical device can selectively switch between various modes, including the transmission mode and the blocking mode, and thus the active liquid crystal layer can be a light modulation layer.

The term external energy refers to energy applied from the outside at a level that can change the orientation of the liquid crystal compound included in the active liquid crystal layer. In one example, the external energy may be an electric field generated by an external voltage induced through the electrode layer.

For example, the active liquid crystal layer switches between the above-mentioned transmission mode and blocking mode, or between other modes, as the orientation state of the liquid crystal compound changes depending on whether the external energy is applied, its size and/or application location, etc. You can switch.

In one example, the active liquid crystal layer may be a liquid crystal layer called a guest host liquid crystal layer. In this case, the active liquid crystal layer may further include an anisotropic dye along with the liquid crystal compound. The guest host liquid crystal layer is a liquid crystal layer using the so-called guest host effect, and is a liquid crystal layer in which the anisotropic dye is aligned according to the orientation direction of the liquid crystal compound (hereinafter referred to as a liquid crystal host). The alignment direction of the liquid crystal host can be adjusted using an alignment film and/or the external energy described above.

The type of liquid crystal host used in the liquid crystal layer is not particularly limited, and general types of liquid crystal compounds applied to implement the guest host effect can be used.

For example, the liquid crystal host may be a smectic liquid crystal compound, a nematic liquid crystal compound, or a cholesteric liquid crystal compound. Generally, nematic liquid crystal compounds can be used. The term nematic liquid crystal compound refers to a liquid crystal compound that has no regularity in the position of the liquid crystal molecules, but can be arranged in order in the direction of the molecular axis, and these liquid crystal compounds are in the form of a rod or disc. It can be.

These nematic liquid crystal compounds are, for example, about 40°C or higher, about 50°C or higher, about 60°C or higher, about 70°C or higher, about 80°C or higher, about 90°C or higher, about 100°C or higher, or about 110°C or higher. One that has a clearing point or a phase transition point in the above range, that is, a phase transition point from the nematic phase to the isotropic phase, may be selected. In one example, the clearing point or phase transition point may be about 160°C or less, about 150°C or less, or about 140°C or less.

The liquid crystal compound may have negative or positive dielectric anisotropy. The absolute value of the dielectric anisotropy may be appropriately selected considering the purpose. For example, the dielectric anisotropy may be greater than 3 or greater than 7, or less than -2 or less than -3.

The liquid crystal compound may also have an optical anisotropy (Δn) of at least about 0.01 or at least about 0.04. In other examples, the optical anisotropy of the liquid crystal compound may be about 0.3 or less or about 0.27 or less.

Liquid crystal compounds that can be used as liquid crystal hosts of the guest host liquid crystal layer are known in the art.

When the liquid crystal layer is the guest host liquid crystal layer, the liquid crystal layer may include an anisotropic dye together with the liquid crystal host. The term “dye” may refer to a material that can intensively absorb and/or modify light within the visible light region, for example, at least part or the entire wavelength range of 380 nm to 780 nm, and the term “anisotropic “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.

As an anisotropic dye, for example, a known dye known to have the property of being aligned depending on the alignment state of the liquid crystal host can be selected and used. For example, the anisotropic dye may be an azo dye or an anthraquinone dye, and the liquid crystal layer may contain one or two or more types of dyes to achieve light absorption in a wide wavelength range.

The dichroic ratio of the anisotropic dye can be appropriately selected considering the purpose. For example, the anisotropic dye may have a dichroic ratio in the range of 5 to 20. The term “dichroic ratio” may mean, for example, in the case of a p-type dye, the absorption of polarized light parallel to the long axis direction of the dye divided by the absorption of polarized light parallel to the direction perpendicular to the long axis direction. The anisotropic dye may have the dichroic ratio at least a portion of the wavelength within the wavelength range of the visible region, for example, about 380 nm to 780 nm or about 400 nm to 700 nm, or at any one wavelength or the entire range. there is.

The content of the anisotropic dye in the liquid crystal layer can be appropriately selected considering the purpose. For example, based on the total weight of the liquid crystal host and the anisotropic dye, the content of the anisotropic dye may be selected within the range of 0.1 to 10% by weight. The ratio of the anisotropic dye can be changed considering the desired transmittance and the solubility of the anisotropic dye in the liquid crystal host.

The liquid crystal layer basically includes the liquid crystal host and anisotropic dye, and, if necessary, may additionally include other additives in known forms. Examples of additives include chiral dopants or stabilizers, but are not limited thereto.

The thickness of the liquid crystal layer may be appropriately selected to suit the desired mode implementation, for example. In one example, the thickness of the liquid crystal layer is about 0.01μm or more, 0.05μm or more, 0.1μm or more, 0.5μm or more, 1μm or more, 1.5μm or more, 2μm or more, 2.5μm or more, 3μm or more, 3.5μm or more, 4μm or more. , 4.5μm or greater, 5μm or greater, 5.5μm or greater, 6μm or greater, 6.5μm or greater, 7μm or greater, 7.5μm or greater, 8μm or greater, 8.5μm or greater, 9μm or greater, or 9.5μm or greater. The upper limit of the thickness of the liquid crystal layer is not particularly limited, and may generally be about 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less.

The active liquid crystal layer or the light modulation film including the same may switch between a first alignment state and a second alignment state different from the first alignment state. The switching can be controlled, for example, through the application of external energy such as voltage. For example, in a state where no voltage is applied, one of the first and second orientation states may be maintained and then switched to another orientation state by applying a voltage.

In one example, the first and second orientation states may be selected from horizontal orientation, vertical orientation, spray orientation, tilt orientation, twisted nematic orientation, or cholesteric orientation, respectively. For example, in blocking mode, the liquid crystal layer or light modulating film is at least horizontally aligned, twisted nematic aligned, or cholesteric aligned, and in transmission mode, the liquid crystal layer or light modulating film is vertically aligned or horizontally aligned in the blocking mode. There is a horizontal orientation state with an optical axis in a different direction. The liquid crystal device may be a device of a normally black mode in which the blocking mode is implemented in a voltage-free state, or a normally transparent mode in which the transmission mode is implemented in a voltage-less state.

The above active liquid crystal layer can have various modes. The active liquid crystal layer may be driven, for example, in Electrically Controlled Birefringence (ECB) mode, Twisted Nematic (TN) mode, or Super Twisted Nematic (STN) mode. It is not limited to this, and the alignment characteristics of the liquid crystal compound in the active liquid crystal layer may vary depending on the driving mode of the active liquid crystal layer.

In one example, in one orientation state of the active liquid crystal layer, the liquid crystal compound exists in a state oriented to form an angle with the absorption axis of the polarizing layer, which will be described later, or is oriented to be horizontal or perpendicular to the absorption axis of the polarizing layer. It may exist in a twisted state, or it may exist in a twisted state.

In this specification, the term “twisted aligned state” means that the optical axis of the active liquid crystal layer has an inclination angle within the range of about 0 degrees to 15 degrees, about 0 degrees to 10 degrees, and about 0 degrees to 5 degrees with respect to the plane of the active liquid crystal layer. Although it is horizontally aligned, the angle of the long axis direction of neighboring liquid crystal compounds included in the active liquid crystal layer changes slightly, which may mean that they are arranged in a twisted manner.

As described above, the alignment characteristics of the liquid crystal compound in the active liquid crystal layer can be changed by the application of an external action.

In one example, in the absence of an external action, if the active liquid crystal layer is horizontally aligned, the transmittance can be increased by switching to a vertical alignment state by applying an external action.

In another example, in the absence of an external action, if the active liquid crystal layer is vertically aligned, the transmittance can be reduced by switching to a horizontal alignment state by the application of an external action. Additionally, when switching from the initial vertical alignment state to the horizontal alignment state, pre-tilt in a certain direction may be required to determine the orientation direction of the liquid crystal compound. The method of providing the free tilt in the above is not particularly limited, and can be done, for example, by arranging an appropriate alignment film to provide the intended free tilt.

In the above state, where the active liquid crystal layer additionally contains an anisotropic dye and the liquid crystal compound is vertically aligned, the alignment direction of the anisotropic dye is perpendicular to the plane of the polarizing layer existing below, so the light passing through the polarizing layer is active. It can be transmitted without being absorbed by the anisotropic dye of the liquid crystal layer, thereby increasing the transmittance of the optical device. On the other hand, when the liquid crystal compound of the active liquid crystal layer is horizontally aligned, the alignment direction of the anisotropic dye is parallel to the plane of the polarizing layer existing below, so the optical axis of the active liquid crystal layer is predetermined with respect to the absorption axis of the polarizing layer. When arranged to have an angle of , part of the light passing through the polarizing layer may be absorbed by the anisotropic dye, thereby reducing the transmittance of the optical device.

In one example, the optical device implements a transmission mode with a transmittance of 15% or more in the visible light region in the presence of an external action, and a blocking mode with a transmittance of 3% or less in the visible light region in the absence of an external action. It can be implemented.

When the active liquid crystal layer operates in TN mode or STN mode, the active liquid crystal layer may additionally include a chiral agent. A chiral agent can induce the molecular arrangement of the liquid crystal compound and/or anisotropic dye to have a helical structure. The chiral agent may be used without particular limitation as long as it can induce the desired helical structure without impairing liquid crystallinity, for example, nematic regularity. A chiral agent to induce a helical structure in a liquid crystal needs to include at least chirality in its molecular structure. Chiral agents include, for example, compounds with one or two or more asymmetric carbons, compounds with an asymetric point on heteroatoms such as chiral amines or chiral sulfoxides, or cumulene. Examples may include compounds having an axially asymetric optically active site with an axial agent such as cumulene or binaphthol. For example, the chiral agent may be a low molecular weight compound with a molecular weight of 1,500 or less. As the chiral agent, commercially available chiral nematic liquid crystals, for example, chiral dopant liquid crystal S-811 available from Merck or LC756 from BASF, etc. may be used.

There is a known method of checking in which direction the optical axis of the liquid crystal layer is formed in the alignment state of the liquid crystal layer. For example, the direction of the optical axis of the liquid crystal layer can be measured using another polarizer whose optical axis direction is known, and this can be measured using a known measuring device, for example, a polarimeter such as Jascp's P-2000. You can.

There is a known method of implementing a liquid crystal device in the above-mentioned normal transmission or blocking mode by adjusting the dielectric anisotropy of the liquid crystal host, the orientation direction of the alignment film that orients the liquid crystal host, etc.

The light modulation film may include a spacer between the two base films, which maintains the gap between the two base films, and/or a spacer that attaches the base films while maintaining the gap between the two opposingly arranged base films. Sealants, etc. may be additionally included. As the spacer and/or sealant, known materials can be used without particular restrictions.

In the light modulation film, an alignment layer may be present on one side of the base film, for example, the side facing the light modulation layer (eg, active liquid crystal layer). For example, the alignment layer may be present on the electrode layer.

The alignment layer is a component for controlling the orientation of the liquid crystal host included in the light modulation layer such as the active liquid crystal layer, and a known alignment layer can be applied without particular restrictions. Alignment layers known in the industry include rubbing alignment layers and photo-alignment layers.

The orientation direction of the alignment film can be controlled to achieve the orientation of the optical axis described above. For example, the orientation directions of the two alignment films formed on each side of the two opposing base films have an angle in the range of about -10 degrees to 10 degrees, an angle in the range of -7 degrees to 7 degrees, and -5 degrees to each other. They may form an angle in the range of 5 degrees, or in the range of -3 degrees to 3 degrees, or may be approximately parallel to each other. In another example, the orientation direction of the two alignment films is an angle in the range of about 80 degrees to 100 degrees, an angle in the range of about 83 degrees to 97 degrees, an angle in the range of about 85 degrees to 95 degrees, or an angle in the range of about 87 degrees to 92 degrees. They may be at an angle or be approximately perpendicular to each other.

Since the direction of the optical axis of the active liquid crystal layer is determined according to this orientation direction, the orientation direction can be confirmed by checking the direction of the optical axis of the active liquid crystal layer.

The optical device may further include a polarizing layer instead of or together with the light modulation film. As the polarizing layer, for example, an absorption-type polarizing layer, that is, a polarizing layer having a light absorption axis formed in one direction and a light transmission axis formed substantially perpendicular thereto, can be used.

Assuming that a polarizing layer and a light modulation film are included together, and that the blocking state is implemented in the first orientation state of the light modulation film, the average optical axis (vector of the optical axis) of the first orientation state and the polarization layer The angle formed by the light absorption axis is 80 degrees to 100 degrees, or 85 degrees to 95 degrees, or is arranged so that it is approximately vertical, or is arranged so that it is 35 degrees to 55 degrees, or about 40 degrees to 50 degrees, or is approximately 45 degrees. There may be.

Based on the orientation direction of the alignment film, the orientation direction of the alignment film formed on each side of the two base films of the light modulation film arranged opposite each other as described above has an angle within the range of about -10 degrees to 10 degrees, -7 degrees. When forming an angle within the range of to 7 degrees, an angle within the range of -5 degrees to 5 degrees, or an angle within the range of -3 degrees to 3 degrees, or are approximately parallel to each other, the orientation direction of any one of the two alignment layers and the polarization The angle formed by the light absorption axis of the layer may be 80 degrees to 100 degrees, 85 degrees to 95 degrees, or may be approximately vertical.

In another example, the orientation direction of the two alignment layers is an angle in the range of about 80 degrees to 100 degrees, an angle in the range of about 83 degrees to 97 degrees, an angle in the range of about 85 degrees to 95 degrees, or an angle in the range of about 87 degrees to 92 degrees. When forming an angle or being approximately perpendicular to each other, the angle formed between the orientation direction of the alignment film disposed closer to the polarizing layer among the two sheets of alignment film and the light absorption axis of the polarizing layer is 80 degrees to 100 degrees or 85 degrees to 95 degrees. It can be horizontal or approximately vertical.

When the light modulation film and the polarization layer are included together, for example, the light modulation film and the polarization layer may be stacked on each other. Additionally, in the above state, the optical axis (average optical axis) of the light modulation film in the first orientation direction may be arranged so that the light absorption axis of the polarizing layer has the above relationship.

In one example, when the polarizing layer is a polarizing coating layer described later, a structure in which the polarizing coating layer exists inside the light modulation film may be implemented. For example, a structure in which the polarization coating layer exists between one of the base films of the light modulation film and the light modulation layer may be implemented. For example, the electrode layer, the polarizing coating layer, and the alignment layer may be sequentially formed on at least one of the two base films of the light modulation film.

The type of the polarizing layer that can be applied in an optical device is not particularly limited. For example, the polarizing layer is a common material used in existing LCDs, such as PVA (poly(vinyl alcohol)) polarizing layer, lyotropic liquid crystal (LLC: Lyotropic Liquid Cystal), or reactive liquid crystal (LLC). A polarizing layer implemented by a coating method, such as a polarizing coating layer containing RM: Reactive Mesogen and a dichroic dye, can be used. In this specification, the polarizing layer implemented by the coating method as described above may be referred to as a polarizing coating layer. As the lyotropic liquid crystal, known liquid crystals can be used without particular restrictions. For example, lyotropic liquid crystals that can form a lyotropic liquid crystal layer with a dichroic ratio of about 30 to 40 can be used. On the other hand, when the polarizing coating layer includes a reactive liquid crystal (RM: Reactive Mesogen) and a dichroic dye, a linear dye or a discotic dye may be used as the dichroic dye. It may be possible.

The optical device of the present application may include one or more of the light modulation film and polarizing layer as described above, or may include both of the above. When both are included, only one of each may be included, or two or more of any of them may be included.

In one example, the optical device may include only one light modulation film and only one polarization layer, but is not limited thereto.

In another example, the optical device of the present application may include two opposing polarization layers, and may have a structure in which the light modulation layer exists between the two polarization layers. In this case, the absorption axes of the two opposing polarizing layers (first and second polarizing layers) may be perpendicular to each other or horizontal. In the above, vertical and horizontal can be understood as actual vertical and horizontal, respectively, and include errors within ±5 degrees, ±4 degrees, ±3 degrees, and ±2 degrees.

The optical device may further include two outer substrates arranged opposite each other. In this specification, for convenience, one of the two outer substrates may be referred to as the first outer substrate, and the other may be referred to as the second outer substrate. However, the first and second expressions do not indicate the order or vertical relationship of the outer substrates. It is not stipulated.

In one example, the light modulation film or the light modulation film and the polarizing layer may be encapsulated between the two outer substrates. This encapsulation can be achieved using an encapsulating agent. For example, as shown in FIG. 9, the light modulation film 10 and the polarizing layer 20 may exist between the two facing outer substrates 30.

As the outer substrate, for example, an inorganic substrate made of glass or a plastic substrate may be used. As a plastic substrate, TAC (triacetyl cellulose) film; COP (cyclo olefin copolymer) films such as norbornene derivatives; Acrylic films such as PMMA (poly(methyl methacrylate)); PC (polycarbonate) film; PE (polyethylene) film; PP (polypropylene) film; PVA (polyvinyl alcohol) film; DAC (diacetyl cellulose) film; Pac (polyacrylate) film; PES (polyetheretherketone) film, PPS (polyetherimide) film, PET (polyethyleneterephtalate) film; PSF (polysulfone) film; A PAR (polyarylate) film or a fluororesin film may be used, but the outer substrate is not limited to this, and if necessary, a coating layer of a silicon compound such as gold, silver, silicon dioxide, or silicon monoxide, or a coating layer such as an anti-reflection layer. This may exist.

The thickness of the outer substrate is not particularly limited and may be, for example, about 0.3 mm or more. In other examples, the thickness may be about 0.5 mm or more, about 1 mm or more, about 1.5 mm or more, or about 2 mm or more, 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 It may be about mm or less, 4 mm or less, or 3 mm or less.

The outer substrate may be a flat substrate or a substrate having a curved shape. For example, the two outer substrates may be flat at the same time, may have a curved shape at the same time, or one may be a flat substrate and the other may be a curved substrate.

In addition, in the case where both surfaces have curved shapes, each curvature or radius of curvature may be the same or different.

In the present specification, the curvature or radius of curvature can be measured by methods known in the industry, for example, non-contact methods such as 2D Profile Laser Sensor, Chromatic confocal line sensor, or 3D Measuring Conforcal Microscopy. It can be measured using equipment. Methods of measuring curvature or radius of curvature using such equipment are known.

In addition, with respect to the substrate, for example, if the curvature or radius of curvature on the front and back surfaces are different, the curvature or radius of curvature of each opposing surface, that is, in the case of the first outer substrate, the surface opposing the second outer substrate In the case of the curvature or radius of curvature and the second outer substrate, the curvature or radius of curvature of the surface facing the first outer substrate may be the standard. Additionally, if the curvature or radius of curvature in the corresponding surface is not constant and different parts exist, the largest curvature or radius of curvature, the smallest curvature or radius of curvature, or the average curvature or radius of curvature may be used as a standard.

The substrate has a difference in curvature or radius of curvature of less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1%. It may be within %. The difference in curvature or radius of curvature is a value calculated as 100×(CL-CS)/CS when the large curvature or radius of curvature is referred to as CL and the small curvature or radius of curvature is referred to as CS. Additionally, the lower limit of the difference in curvature or radius of curvature is not particularly limited. Since the difference in curvature or radius of curvature of the two outer substrates may be the same, the difference in curvature or radius of curvature may be 0% or greater.

Control of the curvature or radius of curvature as described above is useful in structures where the light modulation film and/or the polarizing layer are encapsulated with an encapsulant, such as the optical device of the present application.

When both the first and second outer substrates are curved surfaces, the curvatures of both may have the same sign. In other words, both of the two outer substrates may be bent in the same direction. That is, in the above case, the center of curvature of the first outer substrate and the center of curvature of the second outer substrate are both located in the same portion of the upper and lower portions of the first and second outer substrates.

Figure 2 is a side example in which an encapsulation portion 400 including a light modulation film, etc. exists between the first and second outer substrates 30. In this case, both the first and second outer substrates 30 are present. The center of curvature is at the bottom of the drawing.

The specific range of each curvature or radius of curvature of the first and second outer substrates is not particularly limited. In one example, the radius of curvature of each of the substrates is 100R or more, 200R or more, 300R or more, 400R or more, 500R or more, 600R or more, 700R or more, 800R or more, or 900R or more, or 10,000R or less, 9,000R or less, or 8,000R or more. Below 7,000R, below 6,000R, below 5,000R, below 4,000R, below 3,000R, below 2,000R, below 1,900R, below 1,800R, below 1,700R, below 1,600R, below 1,500R, below 1,400R, It may be 1,300R or less, 1,200R or less, 1,100R or less, or 1,050R or less. In the above, R refers to the bending hardness of a circle with a radius of 1 mm. Thus, for example above, 100R is the degree of curvature of a circle with a radius of 100 mm or the radius of curvature for such a circle. Of course, if the substrate is flat, the curvature is 0 and the radius of curvature is infinite.

The first and second outer substrates may have the same or different radii of curvature in the above range. In one example, when the first and second outer substrates have different curvatures, the radius of curvature of the substrate with the greater curvature may be within the above range.

In one example, when the first and second outer substrates have different curvatures, the substrate with the greater curvature may be the substrate disposed more in the direction of gravity when the optical device is used.

In one example, among the first and second outer substrates, the lower substrate may have a greater curvature than the upper substrate. In this case, the difference in curvature of the first and second outer substrates may be within the range described above. In addition, in the upper part, when both the first and second outer substrates are curved substrates, or when one of the first and second outer substrates is a curved substrate and the other is a flat substrate, the convex portion of the curved surface is It is a positional relationship determined according to the direction it faces. For example, in the case of FIG. 2, since the convex direction is formed from the bottom to the top of the drawing, the upper outer substrate becomes the upper substrate, and the lower outer substrate becomes the lower substrate. In this structure, a certain level of pressure is generated in the center of the optical device due to the restoring force shown by the curved substrate among the outer substrates attached to each other by the encapsulant 400, thereby suppressing and reducing the occurrence of defects such as bubbles inside the optical device. can be alleviated and/or prevented.

For the encapsulation, an autoclave process using an encapsulating agent can be performed, as will be described later, and high temperature and high pressure are usually applied in this process. However, in some cases, such as when the encapsulant applied for encapsulation is stored at high temperature for a long time after such an autoclave process, some re-melting may occur, which may cause the problem of the outer substrate spreading. When this phenomenon occurs, force acts on the encapsulated light modulation film and/or polarizing layer, and bubbles may be formed inside.

However, if the curvature or radius of curvature between the substrates is controlled as above, even if the bonding force caused by the encapsulant decreases, the net force, which is the sum of the restoring force and gravity, acts to prevent opening, and can withstand process pressure such as an autoclave well. You can. In addition, since the net force, which is the sum of the restoring force and gravity, acts at the center of the optical device, the occurrence of defects such as bubbles can be more effectively suppressed, alleviated, alleviated, and/or prevented in the area where the actual transmittance, etc. is controlled.

The optical device may further include an encapsulating agent encapsulating the light modulation film and/or polarizing layer within the outer substrate. This encapsulant 40 is, for example, between the outer substrate 30 and the light modulation film 10, between the light modulation film 10 and the polarizing layer 20, and/or as shown in FIG. 3. It may exist between the polarizing layer 20 and the outer substrate 30, and may exist on the sides of the light modulation film 10 and the polarizing layer 20, and appropriately, on all sides.

The encapsulant adheres the outer substrate 30 and the light modulation film 10, the light modulation film 10 and the polarizing layer 20, and the polarization layer 20 and the outer substrate 30 to each other, and the light modulation film (10) and the polarizing layer (20) may be encapsulated.

Figure 3 is an example of a case where both the light modulation film 10 and the polarization layer 20 are present, but as described above, either one of the light modulation film 10 and the polarization layer 20 may be omitted. .

Accordingly, in this case, the encapsulating agent may be present, for example, between the outer substrate and the light modulation film or polarization layer, and may be present on the sides, appropriately all sides, of the light modulation film or polarization layer.

For example, depending on the desired structure, the above structure can be implemented by stacking an outer substrate, a light modulation film, a polarizing layer, and an encapsulant and then pressing them by applying heat and pressure.

As the encapsulating agent, known materials may be used, for example, adhesive films may be used. Known adhesive films applicable to encapsulation include thermoplastic polyurethane adhesive film (TPU: Thermoplastic Starch), polyamide adhesive film, polyester adhesive film, EVA (Ethylene Vinyl Acetate) adhesive film, polyethylene, or There are polyolefin adhesive films such as polypropylene or polyolefin elastomer films (POE films), and among these known adhesive films, an appropriate one described later can be selected.

As an encapsulating agent, a so-called hot melt type adhesive film may be applied. The hot melt type adhesive film referred to in this specification is a type of film that exists in a solid film state at room temperature, develops fluidity when heat is applied, and hardens when heat is removed again. After placing such a film between two elements to be attached to each other, heat and pressure are applied to bond the elements, and then the heat is removed and hardened to attach the elements using the adhesive film.

As an encapsulating agent, a film having a phase difference in a predetermined range can be used. In one example, the encapsulant may have a frontal retardation of 100 nm or less. In other examples, the front phase difference is about 95 nm or less, about 90 nm or less, about 85 nm or less, about 80 nm or less, about 75 nm or less, about 70 nm or less, about 65 nm or less, about 60 nm or less, about 55 nm or less, about 50 nm or less, about 45 nm or less. , about 40 nm or less, about 35 nm or less, about 30 nm or less, about 25 nm or less, about 20 nm or less, about 15 nm or less, about 10 nm or less, about 9 nm or less, about 8 nm or less, about 7 nm or less, about 6 nm or less, about 5 nm or less , may be about 4 nm or less, about 3 nm or less, about 2 nm or less, or about 1 nm or less. In other examples, the front phase difference is about 0 nm or more, about 1 nm or more, about 2 nm or more, about 3 nm or more, about 4 nm or more, about 5 nm or more, about 6 nm or more, about 7 nm or more, about 8 nm or more, about 9 nm or more, or about 9.5 nm or more. It may be more than nm.

The absolute value of the phase difference in the thickness direction of the encapsulant may be, for example, 200 nm or less. In other examples, the absolute value may be about 190 nm or less, 180 nm or less, 170 nm or less, 160 nm or less, 150 nm or less, 140 nm or less, 130 nm or less, 120 nm or less, or 115 nm or less, or greater than or equal to 0 nm, greater than 10 nm, greater than 20 nm, It may be 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, or 90 nm or more. The thickness direction phase difference may be negative as long as it has an absolute value within the above range, or may be greater than or equal to nm, or may be a positive number.

The front retardation (Rin) and the thickness direction retardation (Rth) of the encapsulant are expressed as thickness (d), slow axis refractive index (nx), fast axis refractive index (ny), and thickness direction refractive index in Equations 1 and 2, respectively ( It can be calculated in the same way, except that nz) is replaced by the thickness of the encapsulant (d), the refractive index in the slow axis direction (nx), the refractive index in the fast axis direction (ny), and the refractive index in the thickness direction (nz).

The thickness of the encapsulant is the thickness of the encapsulant between the outer substrate 30 and the active liquid crystal layer 10, for example, the gap between the two, and the thickness between the light modulation film 10 and the polarizing layer 20. It may be the thickness of the encapsulant, for example, the gap between the two, and the thickness of the encapsulant between the polarizing layer 20 and the outer substrate 30, for example, the gap between the two.

The thickness of the encapsulant is not particularly limited, and may range from about 200 μm to 600 μm, for example. In the above, the thickness of the encapsulant is the thickness of the encapsulant between the outer substrate 30 and the light modulation film 10, for example, the gap between the two, and the thickness between the light modulation film 10 and the polarizing layer 20. It may be the thickness of the encapsulant, for example, the gap between the two, and the thickness of the encapsulant between the polarizing layer 20 and the outer substrate 30, for example, the gap between the two.

The optical device may further include any necessary configuration in addition to the above configuration, and may include, for example, known configurations such as a retardation layer, an optical compensation layer, an anti-reflection layer, and a hard coating layer at appropriate positions.

This application relates to a manufacturing method of the optical device. The manufacturing method includes: the first outer substrate; a first encapsulation film (adhesive film) forming the encapsulant; The light modulation film or polarizing layer; It may include applying heat and pressure to a laminate in which a second encapsulation film (second adhesive film) forming the encapsulant and a second outer substrate are laminated in the above order.

Figures 4 and 5 are schematic diagrams of the above process.

In the manufacturing method of the present application, as shown in FIG. 4, an outer substrate 1001, an adhesive film 2001, an optical element (light modulation film or polarizing layer) 3001, an adhesive film 2002, and an outer substrate 1002 are sequentially stacked. It includes the step of applying heat and pressure to the laminate. The heat and pressure may be applied as shown by the arrows on both the outside of the two outer substrates 1001 and 1002, as shown in the drawing, or may be applied in the direction shown by the arrow to only one of the two outer substrates 1001 and 1002. there is.

In addition, if necessary, an adhesive film 2004 may be additionally placed on the side of the optical element in the above process so that the encapsulant can be present on the side (appropriately all sides) of the optical element (light modulation film or polarizing layer) as shown in the drawing. You can.

When manufacturing an optical device including both the light modulation film 3001 and the polarizing layer 4001, as shown in FIG. 5, the outer substrate 1001, the first adhesive film 2001, the light modulation film 3001, and the third Heat and pressure can be applied in the same manner as above to a laminate in which the adhesive film 2003, the polarizing layer 4001, the second adhesive film 2002, and the outer substrate 1002 are sequentially stacked. In this case as well, heat and pressure may be applied as shown by the arrows on both the outside of the two outer substrates (1001, 1002), or may be applied in the direction shown by the arrow to only one of the two outer substrates (1001, 1002). . Even in the above case, if necessary, the adhesive film 2004 may be disposed on the side of the light modulation film and/or the polarizing layer.

As described above, in the above process, when the curvature or radius of curvature of the outer substrates 1001 and 1002 are different from each other, the substrate with a smaller radius of curvature, that is, a substrate with a larger curvature, may be placed in the direction of gravity.

For example, if the direction from the upper outer substrate 1001 to the lower outer substrate 1002 in Figures 3 and 4 is the direction in which gravity acts, the lower outer substrate 1002 is the upper outer substrate 1002. The laminate may be positioned to have a greater curvature compared to the substrate 1001.

The step of applying heat and pressure to the laminate as described above can usually be performed through an autoclave process.

The conditions of the autoclave process are not particularly limited and, for example, can be performed under appropriate temperature and pressure depending on the type of adhesive film applied. The temperature of a typical autoclave process is approximately 80°C or higher, 90°C or higher, or 100°C or higher, and the pressure is 2 atmospheres or higher, but is not limited thereto. The upper limit of the process temperature may be about 200°C or less, 190°C or less, 180°C or less, or 170°C or less, and the upper limit of the process pressure may be about 10 atmospheres or less, 9 atmospheres or less, 8 atmospheres or less, 7 atmospheres or less, or 6 atmospheres. It may be about the following.

Since the above manufacturing process is a process of encapsulating the optical element inside two relatively rigid outer substrates, defects such as wrinkles, waves, or bubbles occur in the optical element during the encapsulation process. It has a negative effect on the performance of the product.

Accordingly, in the present application, defects such as wrinkles, waves, or bubbles can be prevented by adjusting the manufacturing process conditions or materials.

For example, in one aspect of the present application (hereinafter referred to as the first aspect), softening or melting of at least the first and second encapsulation films (adhesive films) in the process of performing the encapsulation in the above manner. Process conditions are adjusted so that the start times are different. In the above, the first and second encapsulation films are films disposed between the optical element (light modulation film or polarizing layer) and the outer substrate. That is, as can be seen from Figures 4 and 5, according to the process of the present application, there are two adhesive films disposed between the optical element (light modulation film or polarizing layer) and the outer substrate in the laminate, which One of them may be called a first adhesive film (or encapsulation film), and the other may be called a second adhesive film (or encapsulation film). This is simply to distinguish the two adhesive films, and does not indicate any superiority or inferiority relationship between the first and second surfaces.

If encapsulation is performed in this way, the optical element can be effectively and stably encapsulated between two rigid outer substrates, and defects such as waves, wrinkles, or bubbles can be prevented in the process.

In addition to the first and second adhesive films, the softening or melting time of other adhesive films included in the laminate is not particularly limited. That is, the softening start time and/or melting start time of the adhesive films other than the first and second adhesive films may be different from or the same as the remaining first and/or second adhesive films.

In this way, there is no particular limitation on the method of differentiating the starting time of softening and/or melting of the first and second adhesive films.

One method is to use adhesive films having different softening points and/or melting points as the first and second adhesive films. The softening point mentioned in this specification may be a value measured based on the ASTM E2347-004 standard, and the melting point may be a value measured according to the ASTM E794-06 standard.

In this case, even when equal heat is applied during the encapsulation process, the starting point of softening or melting of each adhesive film is different.

The absolute value of the difference in melting point or softening point between the first and second adhesive films having different softening points or melting points may be in the range of about 1°C to 50°C. The absolute value is, in other examples, about 45°C or less, about 40°C or less, about 35°C or less, about 30°C or less, about 25°C or less, about 20°C or less, about 15°C or less, about 10°C or less, or about 1.5℃ or higher, about 2℃ or higher, about 2.5℃ or higher, about 3℃ or higher, about 3.5℃ or higher, about 4℃ or higher, about 4.5℃ or higher, about 5℃ or higher, about 5.5℃ or higher, about 6℃ or higher, about It may be 6.5°C or higher, about 7°C or higher, about 7.5°C or higher, or about 8°C or higher. It is possible to perform an effective process by adjusting the difference in softening point and/or melting point to an appropriate level within the above range in consideration of the applied autoclave process conditions.

The numerical value of each softening point or melting point of the encapsulation film is not particularly limited, and the differences in the above-mentioned absolute values can be shown while having an appropriate softening point and/or melting point in consideration of the autoclave process conditions to be performed among known encapsulation films. Any film can be selected.

As another method, a method of applying substrates having different thermal conductivities as outer substrates can be used. Even in this case, even if equal heat is applied, there is a deviation in the heat conducted to the adhesive film through the outer substrate, so the starting point of softening and/or melting varies. In general, in the case of substrates made of the same material, the thermal conductivity varies depending on the thickness, and since substrates made of different materials have different thermal conductivities, the same material with different thicknesses is applied as the outer substrate, and/or materials of different materials are used. By applying it, the starting point of softening and/or melting can be controlled.

For example, when glass substrates are used as the first and second outer substrates, and the thermal conductivity between them is at the same level, substrates of different thicknesses may be used as each glass substrate.

In this case, the ratio (T1/T2) of the thickness (T1) of the thicker substrate and the thickness (T2) of the thinner substrate among the first and second outer substrates applied to the encapsulation exceeds about 1, It may be in the range of 50 or less. In other examples, the ratio (T1/T2) is 49 or less, 48 or less, 47 or less, 46 or less, 45 or less, 44 or less, 43 or less, 42 or less, 41 or less, 40 or less, 39 or less, 38 or less, 37 or less, 36 or less, 35 or less, 34 or less, 33 or less, 32 or less, 31 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, 21 or less, 20 or less , 19 or less, 18 or less, 17 or less, 16 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, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less. or 2 or less, or 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 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, 19 or more, 20 or more, 21 or more, 22 or more, 23 or more, 24 or more, 25 or more, 26 or more, 27 or more, 28 or more, 29 or more, 30 or more, 31 or more, 32 or more, 33 or more. or more, 34 or more, 35 or more, 36 or more, 37 or more, 38 or more, 39 or more, 40 or more, 41 or more, 42 or more, 43 or more, 44 or more, 45 or more, 46 or more, 47 or more, 48 or more, or 49 or more. It may be possible.

The range of the thickness of the outer substrate itself can be determined within the above-mentioned range, and the manufacturing process can be performed by selecting the outer substrate having the above thickness ratio among the outer substrates of such thickness. In one example, a glass substrate may be used as the substrate having the above thickness ratio.

Alternatively, when performing an autoclave process on the laminate, encapsulation may be performed by applying different amounts of heat to the top and bottom of the laminate, that is, the outside of the first outer substrate and the outside of the second outer substrate. .

When this method is performed, even if the encapsulation film is of the same type, it may soften and/or melt at different times due to the difference in heat applied to the upper and lower parts. The method of controlling the difference in the amount of heat applied to the upper and lower parts is not particularly limited, and a method of varying the process temperature at the upper and lower parts can be applied. In this case, the difference in process temperature can be appropriately selected. there is.

Alternatively, during the encapsulation process, encapsulation may be performed with an insulating process base layer or a thermally conductive process base layer placed on the outside of the first outside substrate and/or outside the second outside substrate so as to be in contact with the outside substrate. It may be possible. These measures have the effect of controlling the thermal conductivity of both outer substrates of the laminate differently, and through this, the melting and/or softening start time of the encapsulation film can be controlled differently.

The insulating eutectic base layer or the thermally conductive eutectic base layer may be disposed only on the outside of one of the first and second outer substrates, or may be disposed on both sides if the effect of providing a difference in thermal conductivity is secured. there is. FIG. 6 is a schematic diagram of the case where the process base layer is disposed on the upper outer substrate 1001 of the laminate of FIG. 4.

The type of the process base layer is not particularly limited and may be appropriately selected. For example, as the insulating process base layer, a base layer having lower thermal conductivity compared to the adjacent outer substrate may be used. For example, when the outer substrate is a glass substrate, considering the thermal conductivity of the applied glass substrate, a base layer having lower thermal conductivity, for example, thermal conductivity in the range of about 0.01 W/mK to 5 W/mK A base layer having a degree can be applied.

These base layers include triacetyl cellulose (TAC) film; COP (cyclo olefin copolymer) films such as norbornene derivatives; Acrylic films such as PMMA (poly(methyl methacrylate)); PC (polycarbonate) film; PE (polyethylene) film; PP (polypropylene) film; PVA (polyvinyl alcohol) film; DAC (diacetyl cellulose) film; Pac (polyacrylate) film; PES (polyetheretherketone) film, PPS (polyetherimide) film, PET (polyethyleneterephtalate) film; PSF (polysulfone) film; Examples may include, but are not limited to, plastic materials such as PAR (polyarylate) film or fluororesin film, porous plastic materials such as expanded polystyrene, expanded polyurethane, and urea foam, and porous insulation materials such as silica airgel.

Meanwhile, as the thermally conductive process base layer, a base layer having a similarly high thermal conductivity compared to the adjacent outer substrate can be used. For example, when the outer substrate is a glass substrate, the thermally conductive process substrate layer is a substrate layer with higher thermal conductivity compared to the glass substrate, and the thermal conductivity is in the range of about 10 W/mK to 1000 W/mK. can be used. These base layers include metal materials such as aluminum, gold, pure silver, tungsten, iron, cast iron, carbon steel, copper, nickel, and platinum, or alumina, ZnO, AlN (aluminum nitride), BN (boron nitride), and silicon nitride. ), ceramic materials such as SiC or BeO, etc. may be exemplified, but are not limited thereto.

There is no particular limitation on the type of the specific insulating or thermally conductive process base layer applied in the process, and a base layer with appropriate characteristics can be selected considering the desired process speed or efficiency.

In this application, by adopting one or two or more of the above methods, the occurrence of defects such as wrinkles, waves, etc., or bubbles in optical elements during the encapsulation process can be suppressed, and the encapsulation process can be effectively performed. .

According to another aspect of the present application (hereinafter referred to as the second aspect), the type of material applied in the encapsulation process, for example, the adhesive film, can be controlled. This control of the type of adhesive film can be performed alone or in conjunction with the first aspect. That is, even when the adhesive film described later is applied, the process of varying the melting and/or softening time of the above-described first and second adhesive films may or may not be applied together.

In the second aspect of the present application, as the adhesive film forming the encapsulant, an adhesive film having an absolute value of deviation in melting point or softening point of 10°C or less can be used. In other examples, the deviation is about 9°C or less, about 8.5°C or less, about 8°C or less, about 7.5°C or less, about 7°C or less, about 6.5°C or less, about 6°C or less, about 5.5°C or less, or about 5°C or less. It may be to some extent. Since the smaller the value of the deviation, the more advantageous, the lower limit is not particularly limited. For example, the deviation may be about 0℃ or higher, 0.5℃ or higher, 1℃ or higher, 1.5℃ or higher, or 2℃ or higher. there is.

The deviation of the melting point and/or softening point is the deviation of the melting point and/or softening point measured for each part of the same adhesive film. For example, the deviation may be a deviation in the melting point and/or softening point shown by each part when the adhesive film is divided into two or more parts having the same area. In the above, the parts of the same area are, for example, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more, or 50 or more. , 45 or fewer, 40 or fewer, 35 or fewer, 30 or fewer, 25 or fewer, 20 or fewer, 15 or fewer, 10 or fewer, 9 or fewer, 8 or fewer, 7 or fewer, 6 or fewer , it may be 5 or fewer, 4 or fewer, 3 or fewer, or 2 or fewer. That is, the present inventors confirmed that variations in melting point and/or softening point occur in each part of commercially available adhesive films depending on the type. The reason is not clear, but it is thought to be because the distribution of additives, etc. applied during the manufacturing process of the adhesive film is not uniform. However, when an adhesive film with a large difference in softening point and/or melting point for each part is applied, defects such as wrinkles, waves, etc., or bubbles in the optical element can easily occur due to uneven softening or melting of the adhesive film during the encapsulation process. It can be triggered. Therefore, it is advantageous for stable encapsulation to apply an adhesive film that does not cause such deviation.

The deviation of the softening point and/or melting point can be confirmed in the following manner. First, cut the adhesive film to obtain two or more specimens with the same area, measure the melting point and/or softening point of each of the obtained specimens, then obtain the arithmetic mean value and standard deviation, and the standard deviation can be used as the deviation. . At this time, the number of divided sheets is not particularly limited and is selected in consideration of the area of the adhesive film, etc., but for example, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more, but 50 or fewer, 45 or fewer, 40 or fewer, 35 or fewer, 30 or fewer, 25 or fewer, 20 or fewer, 15 or fewer, 10 It may be 0 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less.

In another example, a thermoplastic adhesive film that satisfies Equation 1 below may be used as the encapsulating agent.

[Formula 1]

Ta-Tb = 40℃

In Equation 1, Ta is the maximum softening point of the adhesive film according to ASTM E2347-004, and Tb is the minimum softening point of the adhesive film according to ASTM E2347-004.

Equation 1 stipulates that the difference between the minimum and maximum softening points of the adhesive film is within a predetermined range. The smaller the difference between the minimum and maximum softening points, the more uniformly melting and cooling the encapsulation film occurs, thereby reducing wrinkles that occur during the cementation process. It can be prevented effectively.

The lower limit of Equation 1 is not particularly limited because the smaller the value of Equation 1, the better the softening point uniformity of the encapsulation film, but may be, for example, about 0.01°C or about 0.1°C. The upper limit of Equation 1 may be, for example, about 35°C or about 25°C.

In this application, by selecting an adhesive film in the same manner as above and proceeding with the encapsulation process, the occurrence of defects such as wrinkles, waves, etc., or bubbles in optical elements, etc. during the encapsulation process can be suppressed and the encapsulation process can be performed effectively. there is.

The present application also relates to an optical device manufactured by the method described above, and particularly to an optical device to which the method of applying outer substrates of different thicknesses among the methods of the first aspect mentioned above is applied.

Accordingly, the optical device includes the light modulation film and/or polarization layer including a light modulation layer present between the first and second base films disposed opposite each other, and first and second outer substrates, While the light modulation film or polarizing layer has a structure encapsulated by an encapsulating agent between the first and second outer substrates, the first and second outer substrates may have different thicknesses.

Details about the optical device, such as the light modulation film and polarizing layer, the encapsulant, the curvature of the outer substrate, and the thickness ratio, have already been described. The same can be applied.

The above optical devices can be used for various purposes, for example, eyewear such as sunglasses or eyewear for AR (Argumented Reality) or VR (Virtual Reality), the exterior wall of a building, the sunroof of a vehicle, etc. can be used

In one example, the optical device itself may be a sunroof for a vehicle.

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

At this time, if the curvature or radius of curvature of the outer substrates is different from each other, the substrate with a smaller radius of curvature, that is, a substrate with a larger curvature, may be placed more in the direction of gravity.

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, it can be divided into pop-up type sunroof, spoiler (tile & slide) type sunroof, inbuilt type sunroof, folding type sunroof, top-mounted type sunroof, and panoramic roof. Examples may include, but are not limited to, a 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 optical device of the present application, and in this case, specific details about the optical device may be applied in the same manner as those described in the section on the optical device.

This application provides a manufacturing method and optical device of an optical device capable of variable transmittance, and such optical device includes eyewear such as sunglasses, eyewear for AR (Argumented Reality) or VR (Virtual Reality), It can be used for a variety of purposes, such as the exterior walls of buildings or vehicle sunroofs.

1 is a side view of an exemplary light modulating film.
2 and 3 are schematic diagrams of exemplary optical devices.
4 to 6 are diagrams showing the manufacturing process of an optical device.

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

Example 1.

As a light modulation layer, a light modulation film having a GH (Guest-Host) liquid crystal layer was manufactured. Two PC (polycarbonate) films (110, 150 in FIG. 1) on one side of which an ITO (Indium Tin Oxide) electrode layer (120, 140 in FIG. 1) and a liquid crystal alignment layer (not shown in FIG. 1) are sequentially formed are about 12 A mixture of a liquid crystal host (MAT-16-969 liquid crystal from Merck) and a dichroic dye guest (BASF, An optical film was produced by sealing the edges with . The PC films were arranged facing each other so that the sides on which the alignment films were formed faced each other. The GH liquid crystal layer is in a horizontal alignment state when no voltage is applied, and can be switched to a vertical alignment state by applying voltage.

As shown in Figure 5, between the two outer substrates 1001 and 1002, a first encapsulation film (adhesive film) 2001, the light modulation film 3001, a third encapsulation film (adhesive film) 2003, A PVA (polyvinylalcohol)-based polarizing layer (4001) and a second encapsulation film (adhesive film) (2002) were placed to produce a laminate. At this time, an encapsulation film (adhesive film) was also placed on all sides of the light modulation film (3001). 2004) was placed.

In the above, a thermoplastic polyurethane adhesive film (TPU: thermoplastic polyurethane, manufactured by Argotec) with a thickness of 380 ㎛ and a softening point of approximately 76°C was used as the first encapsulation film (2001), and the second and third encapsulation films ( 2003, 2002) and a side-disposition encapsulation film (2004), a polyurethane-based adhesive film (TPU: thermoplastic polyurethane, Covestro's Dureflex A4700) with a thickness of 380 ㎛ and a softening point of about 85°C was used.

In the above, a glass substrate with a thickness of about 3 mm was used as the outer substrate, and a substrate with a radius of curvature of about 1030R (first outer substrate) 1001 and a substrate with a radius of curvature of 1000R (second outer substrate) 1002. was used, and the second outer board was placed in the direction in which gravity acts compared to the first outer board. Afterwards, an autoclave process was performed at a temperature of about 100° C. and a pressure of about 2 atmospheres to manufacture an optical device. Through this process, an optical device with no internal waves or wrinkles and no bubbles was formed.

Example 2.

Instead of using a polyurethane (TPU: thermoplastic polyurethane, Covestro's Dureflex A4700) adhesive film with a thickness of 380 ㎛ and a softening point of about 85°C as all encapsulation films, the first outer substrate has a thickness of about 3.85 mm; An optical device was manufactured in the same manner as in Example 1, except that an in-glass substrate with a radius of curvature of about 1030R was used, and a glass substrate with a thickness of about 0.5 mm and a radius of curvature of about 1000R was used as the second outer substrate. . Through this process, an optical device with no internal waves or wrinkles and no bubbles was formed.

Example 3.

An optical device was manufactured in the same manner as in Example 1 using a polyurethane (TPU: thermoplastic polyurethane, Dureflex A4700 from Covestro) adhesive film with a thickness of 380 ㎛ and a softening point of about 85°C as all encapsulation films. However, the process was performed with a copper film applied to the outside of the first outer substrate 1001 as a process base layer with high thermal conductivity. Through this process, an optical device with no internal waves or wrinkles and no bubbles was formed.

Claims (12)

A light modulation film or polarizing layer including a light modulation layer; and first and second outer substrates, wherein the light modulating film or polarizing layer is encapsulated with an encapsulating agent between the first and second outer substrates,
the first outer substrate; a first encapsulating film forming the encapsulant; The light modulation film or polarizing layer; A step of performing the encapsulation by applying heat and pressure to a laminate in which a second encapsulation film and a second outer substrate forming the encapsulant are laminated in the above order,
The encapsulation is performed so that the softening or melting start times of the first and second encapsulation films are different from each other,
A method of manufacturing an optical device in which an encapsulation step is performed while an insulating process base layer or a thermally conductive process base layer is disposed on the outside of the first outer substrate or the outside of the second outer substrate. The method of claim 1, wherein the laminate includes: a first outer substrate; a first encapsulating film; light modulating film; a third encapsulating film; Polarizing layer; A method of manufacturing an optical device comprising a second encapsulation film and a second outer substrate. 2. The method of claim 1, wherein the first and second encapsulating films have different softening or melting points. 2. The method of manufacturing an optical device according to claim 1, wherein the absolute value of the difference in softening or melting points of the first and second encapsulating films is in the range of 1°C to 50°C. The method of claim 1, wherein the first and second outer substrates have different thicknesses. The method of claim 1, wherein the encapsulation is performed by applying different amounts of heat to the outside of the first outer substrate and the outside of the second outer substrate. The method of claim 1, wherein the thermal conductivity of the process substrate layer is lower than the thermal conductivity of the adjacent outer substrate. The method of claim 1, wherein the thermal conductivity of the process base layer is higher than the thermal conductivity of the adjacent outer substrate. delete The method of claim 1, wherein the encapsulating film is a thermoplastic polyurethane adhesive film, a thermoplastic polyamide adhesive film, a thermoplastic polyester adhesive film, or a thermoplastic polyolefin adhesive film. The method of claim 1, wherein the light modulation layer is an active liquid crystal layer comprising a liquid crystal host and an anisotropic dye guest and capable of switching between a first alignment state and a second alignment state. delete