KR102411602B1 - Optical Device - Google Patents

Abstract

The present application provides an optical device capable of variable transmittance, and the optical device includes sunglasses, eyewear such as AR (Argumented Reality) or VR (Virtual Reality) eyewear, exterior walls of buildings or vehicles It can be used for various purposes such as loops.

Description

Method of manufacturing an optical device {Optical Device}

This application relates to an optical device.

Transmittance variable devices designed to vary transmittance using a liquid crystal compound are known in various ways. For example, a transmittance variable device using a so-called GH cell (Guest host cell) to which a mixture of a host material and a dichroic dye guest is applied is known. Such a transmittance variable device is applied to various uses, including eyewear such as sunglasses or glasses, exterior walls of buildings, or sunroofs of vehicles.

The present application provides a method of manufacturing an optical device. For application to a specific purpose including a sunroof, it may be considered to encapsulate the transmittance variable device between outer substrates, and such encapsulation may be usually performed by an autoclave process using an adhesive film. However, when a substrate formed in a curved shape is used as the outer substrate depending on the purpose, the encapsulation process is not properly performed, or an effective encapsulation structure is not achieved even though the encapsulation process is performed. For example, when an autoclave process is performed in a state in which a curved substrate is applied, defects such as waves or wrinkles occur in the device to be encapsulated, and such defects deteriorate the appearance quality of the device. Accordingly, one object of the present application is to provide a method for efficiently and stably manufacturing an optical device even when a curved substrate is applied as an encapsulation substrate, that is, an outer substrate. In addition, even when the defect problem as described above occurs, a method capable of controlling the curvature of an optical device to which a curved substrate is applied may be required in terms of design, etc., and the present application provides a method that can adequately respond to such a request. can provide

Among the physical properties mentioned in this specification, when the measured temperature or pressure affects the result, unless otherwise specified, the corresponding physical property is measured at room temperature and normal pressure.

The term room temperature refers to a natural temperature that has not been heated or reduced, and may generally be any temperature within the range of about 10° C. to 30° C., about 23° C. or about 25° C. In addition, unless otherwise specified, in the present specification, the unit of temperature is °C.

The term atmospheric pressure is a natural pressure that is not particularly reduced or increased, and generally means a pressure of about 1 atmosphere, such as atmospheric pressure.

The optical device manufactured in the present application is an optical device capable of adjusting transmittance, and is, for example, an optical device capable of at least switching between a transmission mode and a blocking mode.

Hereinafter, an optical device manufactured by the method of the present application will be first described.

The transmission mode of the optical device is a state in which the optical device exhibits a relatively high transmittance, and the blocking mode is a state in which the optical device exhibits a relatively low transmittance.

In one example, the optical device may have a transmittance of about 30% or more, about 35% or more, about 40% or more, about 45% or more, or about 50% or more in the transmission mode. In addition, the optical device may have a transmittance of about 20% or less, about 15% or less, or about 10% or less in the blocking mode.

In the transmittance mode, the higher the numerical value, the more advantageous, and the lower the transmittance in the blocking mode, the more advantageous, so the respective upper and lower limits 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 can be 10%.

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

The light whose transmittance is controlled in the optical device of the present application may be ultraviolet light, visible light, or near infrared light in the UV-A region. According to a commonly used definition, ultraviolet light in the UV-A region is used to mean radiation having a wavelength within the range of 320 nm to 380 nm, and visible light means radiation having a wavelength within the range of 380 nm to 780 nm. and near-infrared rays are used to mean radiation having a wavelength within the range of 780 nm to 2000 nm.

The optical device of the present application is designed to be able to switch between at least the transmission mode and the blocking mode. If necessary, the optical device is designed to implement various third modes other than the above-mentioned transmission and blocking modes, for example, a mode capable of exhibiting any transmission between the transmission and blocking modes of transmission and the like. can be

Switching between these modes can be achieved using an active liquid crystal film and/or a polarizer. In the above, the active liquid crystal film is a liquid crystal device capable of switching between the alignment states of at least two or more optical axes, for example, the first and the second alignment states. In the above, the optical axis may mean the long axis direction when the liquid crystal compound included in the liquid crystal layer of the liquid crystal film is of a rod type, and in the case of a discotic type, it may mean the normal direction of the plane of the disk. have. For example, when the liquid crystal element includes a plurality of liquid crystal compounds whose optical axes have different directions in a certain alignment state, the optical axis of the liquid crystal element may be defined as an average optical axis, and in this case, the average optical axis is the optical axis of the liquid crystal compounds. It can mean vector sum.

In the active liquid crystal film as described above, the alignment state may be changed by application of energy, for example, application of voltage. For example, the active liquid crystal film may have one alignment state among the first and second alignment states in a state where no voltage is applied, and may be switched to another alignment state when a voltage is applied.

The blocking mode may be implemented in any one of the first and second alignment states, and the transmission mode may be implemented in the other alignment state.

For convenience, in this specification, it is described that the blocking mode is implemented in the first state.

The active liquid crystal film may include a liquid crystal layer including at least a liquid crystal compound. In one example, the liquid crystal layer is a so-called guest host liquid crystal layer, and may be a liquid crystal layer including a liquid crystal compound and an anisotropic dye.

The liquid crystal layer is a liquid crystal layer using a so-called guest host effect, and is a liquid crystal layer in which the anisotropic dye is aligned according to the alignment direction of the liquid crystal compound (hereinafter, may be referred to as a liquid crystal host). The alignment direction of the liquid crystal host may be adjusted depending on whether the above-described external energy is applied.

The type of the liquid crystal host used in the liquid crystal layer is not particularly limited, and a general type of liquid crystal compound applied to realize the guest host effect may be used.

For example, as the liquid crystal host, a smectic liquid crystal compound, a nematic liquid crystal compound, or a cholesteric liquid crystal compound may be used. In general, a nematic liquid crystal compound may be used. The term nematic liquid crystal compound refers to a liquid crystal compound that has no regularity with respect to the positions of liquid crystal molecules, but can be arranged in an orderly manner in the molecular axis direction, and the liquid crystal compound has a rod or discotic shape. can be

Such a nematic liquid crystal compound may be, for example, at least about 40°C, at least about 50°C, at least about 60°C, at least about 70°C, at least about 80°C, at least about 90°C, at least about 100°C, or at least about 110°C. One having a clearing point or a phase transition point in the above range, that is, a phase transition point from a nematic phase to an isotropic phase may be selected. In one example, the clearing point or the 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 a negative or positive dielectric anisotropy. The absolute value of the dielectric anisotropy may be appropriately selected in consideration of the purpose. For example, the dielectric anisotropy may be greater than 3 or greater than 7, or less than -2 or less than -3.

A liquid crystal compound that can be used as a liquid crystal host of the guest host liquid crystal layer is known to those skilled in the art, and can be freely selected from them.

The liquid crystal layer may include an anisotropic dye together with the liquid crystal host. The term "dye" may mean a material capable of intensively absorbing and/or transforming light within the visible light region, for example, at least a part or the entire range within the wavelength range of 380 nm to 780 nm, and the term "anisotropy" The "dye" may refer to a material capable of anisotropic absorption of light in at least a part or the entire range of the visible light region.

As the anisotropic dye, for example, a known dye known to have a property that can be aligned according to the alignment state of the liquid crystal host may be selected and used. For example, an azo dye or anthraquinone dye may be used as the anisotropic dye, and in order to achieve light absorption in a wide wavelength range, the liquid crystal layer may include one or more dyes.

The dichroic ratio of the anisotropic dye may be appropriately selected in consideration of the purpose. For example, the anisotropic dye may have a dichroic ratio of 5 or more to 20 or less. The term "dichroic ratio" may mean a value obtained by dividing absorption of polarized light parallel to the long axis direction of the dye by absorption of polarized light parallel to the direction perpendicular to the long axis direction in the case of p-type dye, for example. The anisotropic dye may have the dichroic ratio in at least a part of the wavelength or at any one wavelength or the entire range within the wavelength range of the visible light region, for example, within the wavelength range of about 380 nm to 780 nm or about 400 nm to 700 nm. have.

The content of the anisotropic dye in the liquid crystal layer may be appropriately selected in consideration of 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 may be changed in consideration of the desired transmittance and solubility of the anisotropic dye in the liquid crystal host.

The liquid crystal layer basically includes the liquid crystal host and the anisotropic dye, and, if necessary, may further include other optional additives according to a known form. Examples of the additive may include, but are not limited to, a chiral dopant or a stabilizer.

The thickness of the liquid crystal layer may be appropriately selected in consideration of a purpose, for example, a desired degree of anisotropy. In one example, the thickness of the liquid crystal layer is about 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, 0.5 μm or more, 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more. , 4.5 μm or more, 5 μm or more, 5.5 μm or more, 6 μm or more, 6.5 μm or more, 7 μm or more, 7.5 μm or more, 8 μm or more, 8.5 μm or more, 9 μm or more, or 9.5 μm or more. By controlling the thickness in this way, an optical device having a large difference between transmittance in a transmissive state and transmittance in a blocked state, that is, a device having a large contrast ratio can be implemented. The thickness is not particularly limited as it is possible to implement a high contrast ratio as the thickness increases, but in general, it may 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 active liquid crystal film including the same as described above may switch between a first alignment state and a second alignment state different from the first alignment state. The switching may be controlled, for example, through application of external energy such as a voltage. For example, any one of the first and second alignment states may be maintained in a state in which no voltage is applied, and then switched to another alignment state by application of a voltage.

The first and second alignment states, in one example, may be selected from a horizontal alignment, a vertical alignment, a twisted nematic alignment, or a cholesteric alignment, respectively. For example, the liquid crystal element or liquid crystal layer in blocking mode is at least horizontally aligned, twisted nematically or cholesteric, and in transmissive mode, the liquid crystal device or liquid crystal layer is vertically aligned or different from the horizontal alignment of the blocking mode. It may be in a horizontal alignment state with optical axes in different directions. The liquid crystal device may be a device of a normally black mode in which the blocking mode is implemented in a state in which no voltage is applied, or may implement a normally transparent mode in which the transmission mode is implemented in a state in which no voltage is applied.

A method of confirming in which direction the optical axis of the liquid crystal layer is formed in the alignment state of the liquid crystal layer is known. For example, the direction of the optical axis of the liquid crystal layer can be measured using another polarizing plate that knows the optical axis direction, which can be measured using a known measuring device, for example, a polarimeter such as Jascp's P-2000. can

A method of realizing a liquid crystal device in a normal transmission or blocking mode as described above by controlling the dielectric anisotropy of the liquid crystal host, the alignment direction of an alignment layer that aligns the liquid crystal host, and the like is known.

The active liquid crystal film may include two base films disposed to face each other and the active liquid crystal layer present between the two base films. In addition, the active liquid crystal film is formed by attaching the base film to a spacer that maintains a gap between the two base films and/or the two base films disposed opposite to each other between the two base films in a state where the gap is maintained. It may further include a sealant. As the spacer and/or sealant, a known material may be used without any particular limitation.

As the base film, for example, an inorganic film or a plastic film made of glass or the like can be used. As the plastic film, TAC (triacetyl cellulose) film; COP (cyclo olefin copolymer) films such as norbornene derivatives; Acrylic film 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 (poly ether sulfone) film; PEEK (polyetheretherketon) film; PPS (polyphenylsulfone) film, PEI (polyetherimide) film; PEN (polyethylenemaphthatlate) film; PET (polyethyleneterephtalate) film; PI (polyimide) film; PSF (polysulfone) film; A polyarylate (PAR) film or a fluororesin film may be used, but is not limited thereto In the base film, 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 may exist.

The thickness of the base film as described above is not particularly limited, and may be, for example, in the range of about 50 μm to 200 μm.

In the active liquid crystal film, a conductive layer and/or an alignment layer may be present on one surface of the base film, for example, on a surface facing the active liquid crystal layer.

The conductive layer present on the surface of the base film is a configuration for applying a voltage to the active liquid crystal layer, and a known conductive layer may be applied without any particular limitation. As the conductive layer, for example, a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as indium tin oxide (ITO) may be applied. Examples of the conductive layer applicable in the present application are not limited to the above, and all types of conductive layers known to be applicable to liquid crystal devices in this field may be used.

In one example, an alignment layer is present on the surface of the base film. For example, a conductive layer may be first formed on one surface of the base film, and an alignment layer may be formed thereon.

The alignment layer is a configuration for controlling the alignment of the liquid crystal host included in the active liquid crystal layer, and a known alignment layer may be applied without any particular limitation. As the alignment layer known in the industry, there is a rubbing alignment layer or a photo alignment layer, and the alignment layer that can be used in the present application is the known alignment layer, which is not particularly limited.

In order to achieve the above-described alignment of the optical axis, the alignment direction of the alignment layer may be controlled. For example, the orientation direction of the two alignment films formed on each surface of the two base films that are oppositely arranged is an angle within a range of about -10 degrees to 10 degrees, an angle within a range of -7 degrees to 7 degrees, and -5 degrees to each other. angles in the range of 5 degrees, or angles in the range of -3 degrees to 3 degrees, or approximately parallel to each other. In another example, the alignment direction of the two alignment layers is an angle within a range of about 80 degrees to 100 degrees, an angle within a range of about 83 degrees to 97 degrees, an angle within a range of about 85 degrees to 95 degrees, or within a range of about 87 degrees to 92 degrees. They may be angled or approximately perpendicular to each other.

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

The form of the active liquid crystal film having the above configuration is not particularly limited, and may be determined according to the application purpose of the optical device, and is generally in the form of a film or a sheet.

The optical device may include a polarizer. These polarizers may be included alone or together with the active liquid crystal film. As the polarizer, for example, an absorption-type linear polarizer, that is, a polarizer having a light absorption axis formed in one direction and a light transmission axis formed substantially perpendicular thereto may be used.

When the active liquid crystal film and the polarizer are included at the same time, the polarizer is an average optical axis of the first alignment state (a vector of the optical axis) and assuming that the blocking state is implemented in the first alignment state of the active liquid crystal layer The angle formed by the light absorption axis of the polarizer is 80 degrees to 100 degrees or 85 degrees to 95 degrees, or it is arranged in an optical device so as to be approximately vertical, or 35 degrees to 55 degrees or about 40 degrees to 50 degrees, or It may be positioned on the optical device to be approximately 45 degrees.

When the alignment direction of the alignment layer is taken as a reference, the alignment direction of the alignment layer formed on each side of the two base films of the active liquid crystal film disposed oppositely as described above is an angle within the range of about -10 degrees to 10 degrees, -7 degrees with respect to each other When an angle within a range of 7 degrees, an angle within a range of -5 degrees to 5 degrees, or an angle within a range of -3 degrees to 3 degrees, or approximately parallel to each other, the orientation direction of any one of the two alignment layers and the polarizer The angle formed by the light absorption axis may be in the range of 80 degrees to 100 degrees or 85 degrees to 95 degrees, or may be approximately vertical.

In another example, the orientation direction of the two alignment layers is an angle within a range of about 80 degrees to 100 degrees, an angle within a range of about 83 degrees to 97 degrees, an angle within a range of about 85 degrees to 95 degrees, or within a range of about 87 degrees to 92 degrees. When forming an angle or substantially perpendicular to each other, the angle between the alignment direction of the alignment layer disposed closer to the polarizer among the two alignment layers and the light absorption axis of the polarizer is 80 degrees to 100 degrees or 85 degrees to 95 degrees, or , can be approximately vertical.

For example, as shown in FIG. 1 , in a state in which the active liquid crystal film 10 and the polarizer 20 are stacked on each other, the optical axis (average optical axis) in the first alignment direction of the active liquid crystal film 10 and the polarizer The light absorption axis of (20) may be arranged to have the above relationship.

In one example, when the polarizer 20 is a polarizing coating layer to be described later, a structure in which the polarizing coating layer is present inside the active liquid crystal film may be implemented. For example, as shown in FIG. 2 , a structure in which the polarizing coating layer 201 exists between the active liquid crystal layer 120 and any one of the base films 110 of the active liquid crystal film is implemented. can be For example, the above-described conductive layer, the polarizing coating layer 201 and the alignment layer may be sequentially formed on the base film 110 .

The type of the polarizer that can be applied to the optical device of the present application is not particularly limited. For example, as a polarizer, common materials used in conventional LCDs, for example, PVA (poly(vinyl alcohol)) polarizer, etc., or Lyotropic Liquid Cystal (LLC), or reactive liquid crystal (RM: A polarizer implemented by a coating method such as a polarizing coating layer including reactive mesogen) and dichroic dye may be used. In the present specification, the polarizer implemented by the coating method as described above may be referred to as a polarizing coating layer. As the lyotropic liquid crystal, a known liquid crystal may be used without particular limitation, for example, a lyotropic liquid crystal capable of forming a lyotropic liquid crystal layer having a dichroic ratio of about 30 to 40 may be used. On the other hand, when the polarizing coating layer includes a reactive liquid crystal (RM) and a dichroic dye, a linear dye or a discotic dye is used as the dichroic dye. may be

The optical device of the present application may include only one active liquid crystal film and one polarizer, respectively, as described above. Accordingly, the optical device may include only one active liquid crystal film and only one polarizer.

The optical device may further include two outer substrates disposed to face each other. In the present specification, for convenience, any 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. It is not stipulated For example, as shown in FIG. 3 , the active liquid crystal film 10 and the polarizer 20 may exist between the two outer substrates 30 disposed opposite to each other.

The active liquid crystal film and/or the polarizer may be encapsulated between the two outer substrates. Such encapsulation may be accomplished using a known encapsulant such as an adhesive film.

As the outer substrate, for example, an inorganic substrate made of glass or a plastic substrate may be used. As the plastic substrate, a TAC (triacetyl cellulose) film; COP (cyclo olefin copolymer) films such as norbornene derivatives; Acrylic film 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 (poly ether sulfone) film; PEEK (polyetheretherketon) film; PPS (polyphenylsulfone) film, PEI (polyetherimide) film; PEN (polyethylenemaphthatlate) film; PET (polyethyleneterephtalate) film; PI (polyimide) film; PSF (polysulfone) film; A polyarylate (PAR) film, a fluororesin film, etc. may be used, but the present invention is not limited thereto. On the outer substrate, 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 may exist.

The thickness of the outer substrate is not particularly limited, and may be, for example, about 0.3 mm or more. In another example, 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, and 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 It may be on the order of 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 a flat substrate at the same time, 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 of having a curved shape at the same time in the above, each curvature or radius of curvature may be the same or different.

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

In addition, with respect to the substrate, for example, when the curvature or radius of curvature on the front surface and the rear surface are different, the curvature or radius of curvature of the opposite surfaces when forming the optical device, that is, in the case of the first outer substrate, the second The curvature or radius of curvature of the surface facing the outer substrate and the second outer substrate may be based on the curvature or radius of curvature of the surface facing the first outer substrate. In addition, if the curvature or radius of curvature on the corresponding surface is not constant and there are different portions, the largest curvature or radius of curvature or the smallest curvature or radius of curvature or average curvature or average radius of curvature may be used as a reference.

The substrate has a difference in both curvatures or radii of curvature within 10%, within 9%, within 8%, within 7%, within 6%, within 5%, within 4%, within 3%, within 2%, or 1 % or less. The difference in the curvature or radius of curvature is a numerical value calculated as 100Х(CL-CS)/CS when a large curvature or radius of curvature is CL and a small radius or radius of curvature is CS. In addition, the lower limit of the difference in the curvature or the radius of curvature is not particularly limited. Since the difference in the curvature or the radius of curvature of the two outer substrates may be the same, the difference in the curvature or the radius of curvature may be 0% or more or more than 0%.

Control of the curvature or radius of curvature as described above is useful in a structure in which an active liquid crystal film and/or a polarizer is encapsulated with an encapsulant, such as the optical device of the present application.

When both the first and second outer substrates in the optical device have curved surfaces, both curvatures may have the same sign. That is, in the optical device, both of the two outer substrates may be bent in the same direction. That is, in this case, both the center of curvature of the first outer substrate and the center of curvature of the second outer substrate exist in the same portion among the upper and lower portions of the first and second outer substrates.

4 is a side view of an encapsulation portion 400 including an active liquid crystal film, etc., present between the first and second outer substrates 30. In this case, both the first and second outer substrates 30 The center of curvature of is the case in the lower part of the figure.

When the first and/or second outer substrate is a curved substrate, a specific range of curvature or radius of curvature of the curved substrate is not particularly limited. In one example, the radius of curvature of each substrate 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, 900R or more, 1,000R or more, 1,100R or more, 1,200R or more , 1,300R or more, 1,400R or more, 1,500R or more, 1,600R or more, 1,700R or more, 1,800R or more, 1,900R or more, 2,000R or more, 2,100R or more, 2,200R or more, or 2,300R or more, or 10,000R or less; 9,000R or less, 8,000R or less, 7,000R or less, 6,000R or less, 5,000R or less, 4,000R or less, 3,000R or less, 2,000R or less, 1900R or less, 1800R or less, 1,700R or less, 1,600R or less, 1,500R or less or less, 1,400R or less, 1,300R or less, 1,200R or less, 1,100R or less, or 1,050R or less. R used when referring to the curvature in the present specification means the curvature hardness of a circle having a radius of 1 mm. Thus, for example in the above, 100R is the degree of curvature of a circle having a radius of 100 mm or the radius of curvature for such a circle. Of course, when the substrate is flat, the curvature is zero, and the radius of curvature is infinite.

The first and second outer substrates may have the same or different radii of curvature within the above range.

In one example, when the curvatures of the first and second outer substrates are different from each other, a substrate having a larger curvature among them may be a substrate disposed in a direction of gravity rather than when an optical device is used. For the encapsulation, an autoclave process using an adhesive film may be performed as described below, and high temperature and high pressure are usually applied in this process. However, in some cases, such as when the adhesive film applied to the encapsulation is stored at a high temperature for a long time after the autoclave process, some re-melting occurs, which may cause a problem in which the outer substrate is opened. When such a phenomenon occurs, a force may act on the encapsulated active liquid crystal film and/or the polarizer, and bubbles may be formed therein.

However, if the curvature or radius of curvature between the substrates is controlled as above, even if the bonding force due to the adhesive film is lowered, the net force, which is the sum of the restoring force and gravity, acts to prevent the spread, and it can withstand the process pressure such as autoclave well. can

The optical device may further include an encapsulating agent for encapsulating the active liquid crystal film and/or the polarizer in the outer substrate or a gap filling agent to be described later. The encapsulant or gap film agent 40 is, for example, between the outer substrate 30 and the active liquid crystal film 10 and between the active liquid crystal film 10 and the polarizer 20 as shown in FIG. 5 . and/or may be present between the polarizer 20 and the outer substrate 30 , and may be present on the side of the active liquid crystal film 10 and the polarizer 20 , preferably on all sides.

Accordingly, the active liquid crystal film and/or polarizer may be encapsulated by the presence of the encapsulant and/or gap-filling agent on the top and bottom surfaces, and on the sides (e.g., all sides) of the active liquid crystal film and/or polarizer. .

The encapsulant or gap filling agent adheres the outer substrate 30 and the active liquid crystal film 10, the active liquid crystal film 10 and the polarizer 20, and the polarizer 20 and the outer substrate 30 to each other, while the active The liquid crystal film 10 and the polarizer 20 may be encapsulated.

For example, the structure may be implemented by laminating an outer substrate, an active liquid crystal film, a polarizer, and an encapsulant according to a desired structure and then compressing it in a vacuum state.

As the encapsulant, a known material may be used without particular limitation, for example, an adhesive film may be used. For example, known thermoplastic polyurethane adhesive film (TPU: Thermoplastic Polyurethane), TPS (Thermoplastic Starch), polyamide adhesive film, acrylic adhesive film, polyester adhesive film, EVA (Ethylene Vinyl Acetate) adhesive film, polyethylene or poly A polyolefin adhesive film such as propylene, a silicone adhesive film, or a polyolefin elastomer film (POE film) having appropriate physical properties may be selected.

The thickness of the adhesive film as described above is not particularly limited, and may be, for example, in the range of about 200 μm to 600 μm. In the above, the thickness of the adhesive film is the thickness of the adhesive film between the outer substrate 30 and the active liquid crystal film 10 , for example, the distance between the two, and the gap between the active liquid crystal film 10 and the polarizer 20 . The thickness of the adhesive film, for example, the distance between the two, and the thickness of the adhesive film between the polarizer 20 and the outer substrate 30, for example, may be the distance between the two.

The optical device may also further include a gap filling agent. The gap filling agent may be present on the inner surface of the outer substrate, which is particularly a curved substrate. In one example, the gap filling agent may be present on the inner surface of the outer substrate, which is a curved substrate. The inner surface or the inner surface of the outer substrate, which is the curved substrate, may be a surface facing another outer substrate in the optical device among the surfaces of the curved substrate. 6 shows the inner surface of the second outer substrate 200 in a structure in which an active liquid crystal film or a polarizer 400 is encapsulated with an encapsulant 40 between the first outer substrate 30 and the second outer substrate 200 In the form in which the gap filling agent 100 is present. That is, although shown as flat in the drawing, at least the second outer substrate 200 is a curved substrate in the above structure. The other outer substrate 30 may or may not be a curved substrate. In addition, if the other outer substrate 30 is a curved substrate, a gap filling agent may also be present on the inner surface thereof, that is, on the surface facing the second outer substrate 200 . The gap filling agent 100 may be directly present on the surface of the substrate as shown in the drawing, or another element may exist between the gap filling agent 100 and the substrate 200 .

The gap filling agent is an element for controlling the curvature of the surface of the curved substrate. That is, the surface formed by the gap filling agent may have a different curvature from the inner surface of the curved substrate. In the above, the surface of the gap filling agent may be a surface opposite to the surface facing the outer substrate, which is a curved substrate, among the surfaces of the gap filling agent.

In one example, the difference between the radius of curvature of the surface of the gap filling agent and the radius of curvature of the inner surface (inner surface) of the curved substrate may be in the range of 1% to 30%. The difference is in another example 2% or more, 3% or more, 4% or more, 5% or more, 6, 7% or more, or 8% or more, or 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, or 10% or less. The difference in the radius of curvature is a numerical value calculated as 100Х(CL-CS)/CS when the large radius of curvature is CL and the small radius is CS. By adjusting the radius of curvature of the gap filling agent in this way, defects occurring in the process of manufacturing or using an optical device can be solved, and an optical device having a desired radius of curvature can be obtained.

With the above difference, the radius of curvature or curvature of the surface of the gap filling agent may be greater or smaller than the radius of curvature or curvature of the inner surface of the curved substrate.

Such a gap filling agent may be formed in a manner to be described later. For example, the gap filling agent is a thermoplastic polyurethane composition, polyamide composition, polyester composition, EVA (Ethylene Vinyl Acetate) composition, polyolefin composition, silicone resin composition, acrylic resin composition or thermoplastic starch (TPS: Thermoplastic Starch), etc. or may be formed therefrom.

The thickness of the gap filling agent is not particularly limited, and may be appropriately formed in consideration of a desired radius of curvature.

The optical device may further include any necessary configuration in addition to the above configuration, for example, a buffer layer, a retardation layer, an optical compensation layer, an antireflection layer, a known configuration such as a hard coating layer may be included in an appropriate position.

The present application relates to a method of manufacturing the optical device as described above. Accordingly, in the following description, specific details regarding the structure or design of the optical device, its components, and the like, follow the above description.

The manufacturing method of the present application is particularly effectively applied when the first and/or second outer substrates are curved substrates in the structure of the optical device.

That is, the manufacturing method of the present application relates to a manufacturing method of an optical device in which at least one outer substrate is a curved substrate in the structure of the above-described optical device.

For example, the manufacturing method may include: first and second outer substrates disposed to face each other; a method of manufacturing an optical device comprising an active liquid crystal film and/or a polarizer encapsulated by an encapsulant between the first and second outer substrates, wherein at least one of the first and second outer substrates is a curved substrate have.

Accordingly, for parts without specific description in the following manufacturing method items, reference may be made to the optical device.

In the manufacturing method of the present application, the gap filling agent is applied to the inner surface of the first and/or second outer substrate, which is the curved substrate, to form a surface of the gap filling agent having a different curvature from that of the inner surface of the curved substrate. may include. As such, the method of applying or forming the gap filling agent is not particularly limited. For example, the gap filling agent may be manufactured by forming a layer of the materials of the gap filling agent on the inner surface of the curved substrate and molding the layer into a curved surface.

For example, as shown in FIG. 7 , in a state in which the gap filling agent or its material 100 is placed on the curved substrate 200 , the surface 3001 of the mold having a curved surface is brought into contact with the material 100 . A gap filling agent may be formed. At this time, if the material 100 is curable, the curing process may be performed while the surface 3001 is in contact, and if necessary, a process such as vacuum compression may be performed. The specific details of the process to be performed are not particularly limited as determined according to the type of material used. The surface 3001 of the mold may be a release-treated surface, and may be removed after the curing process or the like. At this time, as described above, the material of the gap filling agent is a thermoplastic polyurethane composition, a polyamide composition, a polyester composition, an ethylene vinyl acetate (EVA) composition, a polyolefin composition, a silicone resin composition, an acrylic resin composition, or a thermoplastic starch (TPS: Thermoplastic). Starch) and the like, but is not limited thereto.

As mentioned in the above process, the gap filling agent may be formed so that the difference between the radius of curvature of the inner surface of the curved substrate and the radius of curvature of the surface of the gap filling agent is in the range of 1% to 30%.

The difference is in another example 2% or more, 3% or more, 4% or more, 5% or more, 6, 7% or more, or 8% or more, or 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, or 10% or less, with the same difference as above, the radius of curvature or curvature of the surface of the gap filling agent may be greater or smaller than the radius or curvature of the inner surface of the curved substrate.

The manufacturing method may include encapsulating the active liquid crystal film and/or the polarizer with the encapsulating agent between the curved substrate to which the capping agent is applied and another outer substrate subsequent to the above step.

As the encapsulant in the above, the above-described adhesive film may be used. In addition, the structure of the active liquid crystal film and/or the polarizer to be adhered is not particularly limited, and is determined according to the structure of the desired optical device.

For example, if an optical device having a structure as shown in FIG. 5 is the objective, an adhesive film (or a gap filling agent already formed on the curved substrate) between the outer substrates/active liquid crystal film 10/adhesive film/polarizer (20)/A laminate structure of an adhesive film (or a gap filling agent already formed on the curved substrate) can be formed.

A method of performing the encapsulation step is not particularly limited, and, for example, may be performed by applying a known curing method or other lamination techniques.

That is, by performing curing of the adhesive film in the formed laminate, a desired encapsulation structure can be derived.

The encapsulation method may be an appropriate cementation process, for example, an autoclave process in one example. However, the autoclave process is not necessarily required for the bonding or encapsulation, and other methods may be applied depending on the type of the adhesive film.

The conditions of the autoclave process are not particularly limited, and, for example, may be performed under an appropriate temperature and pressure depending on the type of the applied adhesive film. The temperature of a typical autoclaving process is about 80 ° C. or more, 90 ° C. or more, or 100 ° C. or more, and the pressure is 2 atmospheres or more, 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 is 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.

The optical device as described above may be used for various purposes, and for example, eyewear such as sunglasses or eyewear for AR (Argumented Reality) or VR (Virtual Reality), exterior walls of buildings or sunroofs for vehicles, etc. can be used

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

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

In this case, when the outer substrates have different curvatures or radii of curvature, a substrate having a smaller radius of curvature, that is, a substrate having a larger curvature, may be disposed in the gravitational direction.

The present application provides an optical device capable of variable transmittance, and the optical device includes sunglasses, eyewear such as AR (Argumented Reality) or VR (Virtual Reality) eyewear, exterior walls of buildings or vehicles It can be used for various purposes such as loops.

1 to 6 are exemplary views for explaining the optical device of the present application.
7 is a view for explaining an example of a process of forming a gap filling agent on a curved substrate.

Hereinafter, the present application will be specifically described through Examples and Comparative Examples, but the scope of the present application is not limited to the following Examples.

1. The radius of curvature and how to measure the curvature

In Examples, the radius of curvature was measured using a 2D Profile Laser Sensor (laser sensor), and the curvature was obtained as the reciprocal of the radius of curvature. In addition, the radius of curvature of each of the outer substrates mentioned in the following examples is the radius of curvature of surfaces facing each other during manufacturing of the optical device, and when the radius of curvature is not constant and there are different parts, the most A large radius of curvature was taken as a reference.

Example 1.

The following structure was used for manufacture of an optical device.

Active liquid crystal film: Guest-host liquid crystal element (cell gap: about 12㎛, base film type: PET (poly(ethylene terephthalate) film), liquid crystal/dye mixture type: Merck's MAT-16-969 liquid crystal and anisotropic dye (BASF) company, X12)),

Polarizer: PVA (polyvinylalcohol) linear absorption type polarizer,

First outer substrate: a glass substrate having a thickness of 0.55 mm and a radius of curvature of 2400R

Second outer substrate: a glass substrate with a thickness of 3.85 mm and a radius of curvature of 2400R

Encapsulant (adhesive film): TPU (thermoplastic polyurethane) adhesive film (thickness: about 0.38 mm, manufacturer: Argotec, product name: ArgoFlex)

Encapsulant (OCA): 8146-5 product (3M)

Gap Filling Agent: Silicone-based OCR (Manufacturer: Wacker, Product Name: Lumisil100)

The curvature was controlled by applying the gap filling agent to the surface of the second outer substrate. As shown in FIG. 7 , the gap filling agent 100 is applied to the inner surface of the second outer substrate 200 (the surface facing the first outer substrate when the optical device is manufactured), and the curvature of the release-treated surface 3001 is After the release-treated surface 3001 of the substrate of about 2600R is covered on the gap filling agent 100 and cured by maintaining it at a temperature of about 80° C. for about 1 hour, the release-treated surface 3001 is peeled off Thus, a gap filling agent having a surface of about 2600R was formed. The polarizer, the OCA encapsulant, the active liquid crystal film, the OCA encapsulant, and the first outer substrate are sequentially laminated on the gap filling agent 100 of the second outer substrate 200 to which the gap filling agent is applied to form a laminate prepared. When the laminate was manufactured, the concave portions of the first and second outer substrates were all directed upward. Thereafter, an autoclave process was performed on the laminate at a temperature of about 100° C. and a pressure of about 2 atmospheres to manufacture an optical device.

Example 2.

The following structure was used for manufacture of an optical device.

Active liquid crystal film: Guest-host liquid crystal element (cell gap: about 12㎛, base film type: PET (poly(ethylene terephthalate) film), liquid crystal/dye mixture type: Merck's MAT-16-969 liquid crystal and anisotropic dye (BASF) company, X12)),

Polarizer: PVA (polyvinylalcohol) linear absorption type polarizer,

First outer substrate: a glass substrate with a thickness of 2.1 mm and a radius of curvature of 2400R

Second outer substrate: a glass substrate with a thickness of 3.85 mm and a radius of curvature of 2400R

Encapsulant (adhesive film): TPU (thermoplastic polyurethane) adhesive film (thickness: about 0.38 mm, manufacturer: Argotec, product name: ArgoFlex)

Gap Filling Agent: TPU (thermoplastic polyurethane) adhesive film (thickness: about 0.38 mm, manufacturer: Argotec, product name: ArgoFlex)

As shown in FIG. 7 , the gap filling agent 100 is placed on the inner surface of the second outer substrate 200 (the surface facing the first outer substrate when the optical device is manufactured), and the release treatment of the surface 3001 is performed. After covering the release-treated surface 3001 of the substrate having a curvature of approximately 2600R on the gap filling agent 100, vacuum pressing at a temperature of 120° C. for about 2.5 hours, and peeling the release-treated surface 3001 A gap filling agent having a surface of approximately 2600R was formed. The polarizer, the TPU adhesive film (encapsulating agent), the active liquid crystal film, the TPU adhesive film (encapsulating agent) and the first outer substrate are sequentially laminated on the gap filling agent of the second outer substrate to which the gap filling agent is applied. sieve was prepared. When the laminate was manufactured, the concave portions of the first and second outer substrates were all directed upward.

Thereafter, an autoclave process was performed on the laminate at a temperature of about 100° C. and a pressure of about 2 atmospheres to manufacture an optical device.

Comparative Example 1.

An optical device was manufactured in the same manner as in Example 1, except that a gap filling agent was not applied.

Comparative Example 2.

An optical device was manufactured in the same manner as in Example 2, except that a gap filling agent was not applied.

Evaluate the presence of air bubbles

After making the concave part of the optical device manufactured in the Example or Comparative Example face upward, a heat test followed by a cycling test was performed, and then stored at room temperature for about 35 days to cause white spots caused by air bubbles. It was confirmed whether or not it occurred. In the above heat test, the optical device was left at 100° C. for 168 hours, and the cycling test was performed after maintaining the optical device at 90° C. for 4 hours and then reducing the temperature to -40° C. at a rate of -1° C./min for 4 hours. Maintaining was performed for 10 cycles (relative humidity: 90%) as 1 cycle. As a result of the test, in the case of the Example, white spots did not occur, but in the case of the Comparative Example, it can be confirmed that a large amount of white spots were generated.

Claims (15)

first and second outer substrates disposed to face each other; A method of manufacturing an optical device comprising an active liquid crystal film or a polarizer encapsulated by an encapsulant between the first and second outer substrates, wherein the second outer substrate is a curved substrate,
forming a surface of the gap filling agent having a curvature different from that of the inner surface of the second outer substrate by applying a gap filling agent to the inner surface of the second outer substrate; and encapsulating the active liquid crystal film or the polarizer with the encapsulating agent between the first outer substrates. The method according to claim 1, wherein the difference between the radius of curvature of the inner surface of the second outer substrate and the radius of curvature of the surface of the gap filling agent is in the range of 1% to 30%. The method of claim 1 , wherein a radius of curvature of a surface of the gap filling agent is greater than or smaller than a radius of curvature of an inner surface of the second outer substrate. The method for manufacturing an optical device according to claim 1, wherein the radius of curvature of the inner surface of the second outer substrate is in the range of 100R to 10,000R. The method of claim 1 , wherein the first and second outer substrates are both glass substrates. The method of claim 1 , wherein the first and second outer substrates are both curved substrates. The method of claim 6 , wherein a difference between a curvature or a radius of curvature between the second outer substrate and the first outer substrate is within 10%. The method of claim 6 , wherein curvatures of the first and second outer substrates are different from each other. The method of claim 6 , wherein the laminate is manufactured such that the centers of curvature of the first and second outer substrates are at the same portion among the upper and lower portions of the first and second outer substrates. The method of claim 1, wherein the gap filling agent is a thermoplastic polyurethane composition, a polyamide composition, a polyester composition, an ethylene vinyl acetate (EVA) composition, a polyolefin composition, a silicone resin composition, an acrylic resin composition, or a thermoplastic starch (TPS). A method of manufacturing an optical device. The method of claim 1 , wherein the active liquid crystal film comprises a liquid crystal host and an anisotropic dye guest, and has an active liquid crystal layer capable of switching between a first alignment state and a second alignment state. The method for manufacturing an optical device according to claim 1, wherein an encapsulating agent or a gap filling agent is present on the upper and lower surfaces and sides of the active liquid crystal film or the polarizer. According to claim 1, wherein the encapsulant is a thermoplastic polyurethane adhesive film, polyamide adhesive film, polyester adhesive film, EVA (Ethylene Vinyl Acetate) adhesive film, acrylic curable resin composition, acrylic curable resin film, silicone adhesive film, polyolefin adhesive A method of manufacturing an optical device that is a film or a thermoplastic starch (TPS). The active liquid crystal film according to claim 1, comprising both an active liquid crystal film and a polarizer, wherein the active liquid crystal film has an active liquid crystal layer capable of switching between a first alignment state and a second alignment state, and wherein the polarizer comprises the active liquid crystal film The method of manufacturing an optical device, wherein the optical device is disposed in a laminate such that an angle between the average optical axis of the first alignment state of the layer and the light absorption axis of the polarizer is in the range of 80 degrees to 100 degrees or 35 degrees to 55 degrees. first and second outer substrates disposed to face each other; An active liquid crystal film or a polarizer encapsulated by an encapsulant between the first and second outer substrates,
The second outer substrate is a curved substrate,
and a gap filling agent on the inner surface of the second outer substrate, wherein the surface of the gap filler has a curvature different from that of the inner surface of the second outer substrate.

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