Optical component and method for producing optical component

Abstract

An optical component includes a substrate, and an optical functional layer disposed over the substrate. The optical functional layer includes particles, and has a uniform thickness. When the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less.

Description

OPTICAL COMPONENT AND METHOD FOR PRODUCING OPTICAL COMPONENT

[0001] The present disclosure relates to optical components and methods of producing optical components.

[0002] A coating having a refractive index adjusted according to intended use is provided on a surface of an optical lens or a display.

[0003] For example, Patent Document 1 proposes a production method for an optical component for the purpose of production of an antireflective film including a refractive index gradient film achieving excellent productivity and antireflection properties. In the proposed production method, the optical component includes an antireflective film. The antireflective film includes a refractive index gradient structure layer, and an interference layer disposed between the refractive index gradient structure layer and a transparent substrate. In the refractive index gradient structure layer, a refractive index increases in a thickness direction towards the transparent substrate. The interference layer minimizes reflected light using an interference effect (see, for example, Patent Document 1).

[0004] [Patent Document 1] Japanese Patent No. 6396003

[0005] The present disclosure aims to provide an optical component that can appropriately control the reflectance, has excellent film strength, and has small wavelength dependency of the reflectance.

[0006] According to one aspect of the present disclosure, an optical component includes a substrate, and an optical functional layer disposed over the substrate. The optical functional layer includes particles, and has a uniform thickness. When the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less.

[0007] According to the present disclosure, there can be provided an optical component that can appropriately control the reflectance, has excellent film strength, and small wavelength dependency of the reflectance.

[0008] Fig. 1A is a schematic cross-sectional view illustrating an embodiment of an optical component of the present disclosure.Fig. 1B is a schematic cross-sectional view illustrating another embodiment of the optical component of the present disclosure.Fig. 2A is a schematic cross-sectional view illustrating another embodiment of the optical component of the present disclosure.Fig. 2B is a schematic enlarged view of an interface between layer regions in contact with each other in the optical functional layer of Fig. 2A.Fig. 3A is a schematic top view illustrating an example of a state at the time of landing of droplets of a liquid composition discharged by scanning once in a film formation process of a method for producing an optical component according to one embodiment of the present disclosure.Fig. 3B is a schematic top view illustrating another example of the state at the time of landing of the droplets of the liquid composition discharged by scanning once to form a print pattern in the film formation process of the method for producing the optical component according to one embodiment of the present disclosure.Fig. 4A is a schematic cross-sectional view illustrating a state after an optical functional layer formation process in the method for producing the optical component according to one embodiment of the present disclosure.Fig. 4B is a schematic top view illustrating print patterns for forming respective layers of Fig. 4A.Fig. 5A is a schematic side view illustrating a process of discharging droplets of a low refractive index liquid composition 41 from a second inkjet head and curing the low refractive index liquid composition 41 on an optical functional layer composed of a 100% cured state of droplets of a high refractive index liquid composition 42 discharged from a first inkjet head.Fig. 5B is a schematic side view illustrating a process of discharging droplets of a low refractive index liquid composition 41 from a second inkjet head and curing the low refractive index liquid composition 41 on an optical functional layer composed of a 50% cured state of droplets of a high refractive index liquid composition 42 discharged from a first inkjet head.Fig. 6A is a schematic side view illustrating a process of discharging droplets of a low refractive index liquid composition 41 for a second layer and curing the low refractive index liquid composition 41 on a first layer of an optical functional layer in a 100% cured state.Fig. 6B is a schematic side view illustrating a process of discharging droplets of a low refractive index liquid composition 41 for a second layer, and curing the low refractive index liquid composition 41 on a first layer of an optical functional layer in a 50% cured state.Fig. 7 is a schematic view illustrating discharge data in Examples.Fig. 8 is a schematic cross-sectional view illustrating a state after an optical functional layer formation process in the method for producing the optical component according to another embodiment of the present disclosure.

[0009] In the optical component including the antireflective film, which is disclosed in Patent Document 1, a refractive index of the refractive index gradient structure layer and a refractive index of the interference layer are discontinuous. Therefore, there is a concern that wavelength dependency of the reflectance may be caused. In addition, there is a case where the reflectance of the optical component may become approximately 1% depending on a wavelength range, and therefore an improvement is desired. Further, a moth-eye structure optical component having a microscopic convex-concave structure has been widely used. However, further improvement in durability of the moth-eye structure optical component is desired.

[0010] The optical component of the present disclosure can sufficiently solve various concerns in the related art. More specifically, an optical component with which the reflectance can be controlled as desired, and which has small wavelength dependency of the reflectance can be obtained. In addition, the optical component also excels in film strength that is a fundamental quality.

[0011] The details of the present disclosure will be described hereinafter.

[0012] (Optical component) The optical component according to a first embodiment of the present disclosure includes a substrate and an optical functional layer, which includes particles and has a uniform thickness, disposed over the substrate, and may further include other layers or other members, as necessary.

[0013] <Substrate> The substrate is not particularly limited, and may be appropriately selected according to the intended purpose. The substrate is preferably transparent. Specific examples of the substrate include acylated cellulose films (e.g., cellulose triacetate films, cellulose diacetate films, cellulose acetate butylate films, and cellulose acetate propionate films), polyethylene terephthalate films, polyether sulfone films, polyacrylic resin films, polyurethane resin films, polyester films, polycarbonate films, polysulfone films, polyether films, polymethyl pentene films, polyether ketone films, cyclo olefin polymers, (meth)acrylonitrile films, polyolefin, polymers having an alicyclic structure (e.g., norbornene resins), transparent glass, and the like.

[0014] The refractive index of the substrate is not particularly limited. The refractive index of the substrate is preferably 1.40 or greater and 1.75 or less, and more preferably 1.45 or greater and 1.70 or less. Since the refractive index of the substrate is 1.40 or greater and 1.75 or less, a difference in refractive index between the substrate and the optical functional layer can fall within a preferable range.

[0015] A method for measuring the refractive index of the substrate is not particularly limited, and may be appropriately selected according to the intended purpose. The refractive index of the substrate can be measured, for example, by a spectroscopic ellipsometer M-2000 (produced by J. A. Woollam Japan), a spectrophotometer (V-770, produced by JASCO Corporation), or the like.

[0016] An average thickness of the substrate is not particularly limited, and may be appropriately set according to the intended purpose. In view of increase in transmittance, the average thickness of the substrate is preferably 25 μm or greater and 1,000 μm or less, more preferably 25 μm or greater and 250 μm or less, and yet more preferably 30 μm or greater and 90 μm or less.

[0017] A method for measuring the thickness of the substrate is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the thickness of the substrate can be measured by a physical or optical method using a stylus surface profiler (Alpha-Step D-500, produced by ULVAC, Inc.), light interferometric thickness gauge (heliInspect, produced by Heliots AG), or the like, or observing a cross-section of the substrate under a Schottky field emission scanning electron microscope (Schottky FE-SEM). In the present specification, the average value of measured values of the thickness at 3 locations that are randomly selected on the substrate 1 is determined as the average thickness of the substrate.

[0018] A width, size, and shape of the substrate are not particularly limited, and may be appropriately set according to the intended use of the optical component.

[0019] In the case where the substrate has a configuration such that a refractive index is changed in a thickness direction of the substrate, when the substrate is divided into substrate layer regions by 100 nm or less from the bottom surface of the substrate in the thickness direction of the substrate, a difference in refractive index between at least one pair of the substrate layer regions in contact with each other is preferably greater than 0 and 0.1 or less. Since the substrate has the above configuration, transmittance can be increased, and wavelength dependency can be reduced. In the case where a total thickness of the substrate is less than 200 nm, the substrate may be evenly divided into two, and a difference in refractive index between the two substrate layer regions may be determined.

[0020] In the present specification, the phrase “direction intersecting the thickness direction of the substrate” preferably indicates a direction perpendicular to the thickness direction of the substrate, i.e., a planar direction of the surface of the substrate.

[0021] In the case where an optical functional layer is disposed over only one side of the substrate, the bottom surface of the substrate refers to a surface of the substrate on the opposite side to the interface between the substrate and the optical functional layer. In the case where optical functional layers are respectively disposed over both sides of the substrate, the bottom surface of the substrate refers to any surface selected from both surfaces of the substrate.

[0022] A method for measuring the difference in refractive index between substrate layer regions of the substrate is the same as the method for measuring the difference in refractive index between layer regions of the optical functional layer.

[0023] <Optical functional layer> The optical functional layer is disposed over the substrate. The optical functional layer includes particles, and has a uniform thickness. The optical functional layer being disposed over the substrate means that the optical functional layer is disposed directly on, or is disposed above the substrate with one or more layers being interposed between the substrate and the optical functional layer. The optical functional layer is preferably disposed directly on the substrate.

[0024] When the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less. In the case where the optical functional layer is disposed directly on the substrate, the optical functional layer may be divided into layer regions by dividing the optical functional layer by 100 nm from an interface between the substrate and the optical functional layer in the thickness direction of the optical functional layer. The “layer regions” refers to individual regions of layers when the optical functional layer is divided into the layers in the thickness direction of the optical functional layer.

[0025] In the present specification, the phrase “having a uniform thickness” refers to having the undulation of 80 nm or less. The undulation refers to a convex-concave structure in which recesses and bumps are alternately arranged, at the surface. The convex-concave structure is generally referred to as a moth-eye structure. The uniform thickness of the optical functional layer is preferably 60 nm or less, and more preferably 40 nm or less.

[0026] In the present specification, the phrase “thickness direction of the optical functional layer” includes the direction from the interface between the substrate and the optical functional layer toward the substrate side (may be referred to as a “minus thickness direction of the optical functional layer” hereinafter), and the direction from the interface between the substrate and the optical functional layer toward the exposed surface side of the optical functional layer (may be referred to as a “plus thickness direction of the optical functional layer” hereinafter). In the case where the optical functional layer is divided into layer regions, the thickness direction refers to the plus thickness direction of the optical functional layer.

[0027] Each layer region is preferably within the optical film thickness represented by the following equation for readily obtaining a low reflective effect. In the following equation, λ is a wavelength of target light of antireflection performed by the optical component of the present invention. Optical film thickness (nd) = λ / 4

[0028] Therefore, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less. In the case where a total thickness of the optical functional layer is less than 200 nm, the optical functional layer may be evenly divided into two, and a difference in refractive index between the two layer regions may be determined.

[0029] Note that the refractive index in the optical functional layer is not necessarily continuously changed. The optical functional layer may include a layer region with which a refractive index is not changed between the layer regions in contact with one another. In other words, as long as the difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less among all of the layer regions, a difference in refractive index between one layer region and another layer region in contact with the one layer region may be 0. In the case where the optical functional layer is divided into three layer regions, for example, a difference in refractive index between the first layer region and the second layer region may be greater than 0 and 0.1 or less, and a difference in refractive index between the second layer region and the third layer region may be 0. The same is applied to the case where the optical functional layer is divided into four layer regions. Specifically, among the layer regions of the optical functional layer, one or more layer regions that form the refractive index difference of 0 with the adjacent layer region may be included, as long as the difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less.

[0030] In the case where the optical component is adjusted to have low reflectance, a difference between the maximum value and the minimum value of the refractive index of the optical functional layer is preferably 0.2 or greater in view of improvement in a low reflective effect. In the case where the optical component is adjusted to have high reflectance, the difference is preferably 0.4 or greater in view of improvement in a high reflective effect.

[0031] Moreover, a difference in refractive index between the substrate and the layer region of the optical functional layer in contact with the substrate is preferably 0.1 or less.

[0032] As described in the below-described method for producing the optical component, the optical functional layer is suitably formed by repeating a film formation process and a film curing process two or more times. Accordingly, the optical functional layer has a stack structure. The difference in refractive index between the layer regions of the optical functional layer is formed owing to the method for producing the optical component.

[0033] By setting the difference in the refractive index between at least one pair of the layer regions in contact with each other in the optical functional layer to greater than 0 and 0.1 or less, the refractive index can be gradually changed from the layer region closest to the substrate to the layer region present at the outermost surface of the optical functional layer, and interface reflection between the layer regions can be minimized. Specifically, the optical component of the present disclosure can realize optical functions of a moth-eye structure without having the moth-eye structure, and has excellent film strength, such as adhesion and scratch resistance. In the case where the optical functional layer is disposed directly on the substrate, the layer region closest to the substrate refers to the layer region in contact with the substrate.

[0034] In the case where a light condensing function, a function of eliminating undesired light, or the like is imparted to window glass, a solar panel, or the like using the optical component of the present disclosure, and in the case where the substrate is a lens, the substrate may have a configuration in which the refractive index is changed in the thickness direction of the substrate in a similar manner as the optical functional layer. Examples of the lens include glass lenses, and plastic lenses of a cycloolefin polymer, polycarbonate, and the like.

[0035] A method for measuring the difference in the refractive index between layer regions in the optical functional layer is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the refractive index can be measured by a spectroscopic ellipsometer M-2000 (produced by J.A. Woollam Japan), a spectrophotometer (V-770, produced by JASCO Corporation), or the like. A specific example of the measuring method is as follows.

[0036] First, the total film thickness of the optical functional layer is determined by a measuring method, such as a physical or optical method using a stylus surface profiler (Alpha-Step D-500, produced by ULVAC, Inc.), a light interferometric thickness gauge (heliInspect, produced by Heliots AG), or the like, or observing a cross-section of the optical functional layer under a Schottky field emission scanning electron microscope (Schottky FE-SEM). A refractive index of the entire optical functional layer is measured by a spectroscopic ellipsometer M-2000 or a spectrophotometer, and the total film thickness is input during the analysis. The analysis data with a horizontal axis representing the total film thickness and a vertical axis representing the refractive index distribution is acquired, and a difference in the refractive index between layer regions is calculated.

[0037] In the case where the optical functional layer includes particles, the refractive index difference between each pair of layer regions in the optical functional layer can be measured in the following method. First, a concentration of the particles in each of the layer regions from the layer region at the outermost surface to the layer region at the side of the substrate is calculated by image processing of image data acquired by two-dimensional cross-section observation using a Schottky field emission scanning electron microscope (Schottky FE-SEM), or by processing a sample by a focused ion beam device to expose a cross-section, and performing a three-dimensional cross-section observation using a scanning electron microscope (FIB / SEM cross beam device NVision40, produced by Carl ZEISS (SII-NT)). Subsequently, three types of films with the concentration of the particles being varied are prepared, and the films are subjected to measurement by a spectroscopic ellipsometer M-2000 or a spectrophotometer. The relational expression between the particle concentration and the refractive index is calculated from the obtained data, and the refractive index is estimated based on the previously determined particle content. Based on the refractive index obtained by the calculation, a difference in refractive index between each pair of the layer regions in the optical functional layer is calculated.

[0038] An average thickness of the optical functional layer of the present disclosure is not particularly limited, and may be appropriately selected according to desired optical functions. In view of increase in productivity and transmittance, the average thickness of the optical functional layer is preferably 10 nm or greater and 100 μm or less, more preferably 20 nm or greater and 10 μm or less, yet more preferably 30 nm or greater and 1 μm or less, and particularly preferably 50 nm or greater and 500 nm or less.

[0039] A method for measuring the thickness of the optical functional layer is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the thickness of the optical functional layer can be measured by a physical or optical method using a stylus surface profiler (Alpha-Step D-500, produced by ULVAC, Inc.), a light interferometric thickness gauge (heliInspect, produced by Heliots AG), or the like, or observing a cross-section of the optical functional layer under a Schottky field emission scanning electron microscope (Schottky FE-SEM). In the present specification, the average value of measured values of the thickness at 3 locations that are randomly selected on the optical functional layer is determined as the average thickness of the optical functional layer.

[0040] A refractive index of each of the layer regions of the optical functional layer is not particularly limited. The refractive index of each of the layer regions is preferably 1.0 or greater and 2.5 or less, and more preferably 1.2 or greater and 2.0 or less. When the refractive index of each of the layer regions of the optical functional layer is 1.0 or greater, the number of processes for producing the optical component (sol-gel method, etc.) is less likely to be increased for achieving the refractive index. When the refractive index of the optical component is 2.5 or less, production of an optical component is easily performed, and transparency of the optical component can be maintained.

[0041] A method for measuring the refractive index of the optical functional layer is not particularly limited, and may be appropriately selected according to the intended purpose. The refractive index of the optical functional layer can be measured, for example, by a spectroscopic ellipsometer M-2000 (produced by J. A. Woollam Japan), a spectrophotometer (V-770, produced by JASCO Corporation), or the like.

[0042] The optical functional layer of the optical component of the present invention can be formed by applying a liquid composition onto the substrate. As the liquid composition, a liquid composition described in the below-described section of (Method for producing optical component) is suitably used.

[0043] <<Particles>> The particles included in the optical functional layer may be one group of the particles, or two or more groups of particles. The phrase “two or more groups of the particles” used in the present specification refers to two or more groups of the different particles, when the particles having the same or similar properties are classified into groups. The optical functional layer may have a region in which the particles are not included, but the particles are preferably included in the entire region of the optical functional layer. More preferably, the particles are included in the layer region present at the outermost surface of the optical functional layer. The layer region present at the outermost surface of the optical functional layer refers to the layer region at a surface of the optical functional layer that is on the opposite side to the surface of the optical functional layer in contact with the substrate in the thickness direction of the optical functional layer. Yet more preferably, the particles are exposed at the outermost surface of the optical functional layer. According to the above preferable configurations, the refractive index at the surface of the optical component can be further reduced.

[0044] A concentration of the particles in the optical functional layer is preferably changed in the thickness direction of the optical functional layer. The concentration of the particles in the optical functional layer more preferably increases or decreases in the direction from the layer region closest to the substrate to the layer region present at the outermost surface of the optical functional layer.

[0045] In the case where two or more groups of the particles are included in the optical functional layer, a total concentration of the two or more groups of the particles is preferably changed in the thickness direction of the optical functional layer. In the case where the optical functional layer includes two or more groups of the particles, a total concentration of two or more groups of the particles more preferably increases or decreases in the direction from the layer region closest to the substrate to the layer region present at the outermost surface of the optical functional layer.

[0046] In the case where one group of the particles are included in the optical functional layer, for example, a pair of the layer regions in contact with each other in the optical functional layer preferably have different concentrations of the particles from each other.

[0047] In the case where the optical functional layer includes two or more groups of the particles having different refractive indices, for example, a pair of the layer regions in contact with each other in the optical functional layer preferably have different concentrations of the two or more groups of the particles having different refractive indices from each other. The different concentrations of the two or more groups of the particles having different refractive indices may include an embodiment where a concentration of one group of the particles is 0 among the two or more groups of the particles having different refractive indices. In the case where the optical functional layer includes two or more groups of the particles having different refractive indices, a pair of the layer regions in contact with each other preferably includes the particles having different refractive indices from each other. Specifically, the particles included in one layer region preferably have a different refractive index from the particles included in the other layer region in contact with the one layer region.

[0048] In the case where the optical functional layer includes two or more groups of the particles having different refractive indices, for example, a ratio of the concentration of one group of the particles to the concentration of another group of the particles having a different refractive index to the one group of the particles preferably increases or decreases in the direction from the layer region closest to the substrate to the layer region present at the outermost layer of the optical functional layer.

[0049] A method for measuring the refractive index of the particles is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the refractive index of the particles can be measured by Abbemat MW (produced by Anton Paar GmbH), Abbe refractometer (produced by ATAGO CO., LTD.), or the like.

[0050] In the case where the optical functional layer includes two or more groups of the particles, the optical functional layer preferably includes two or more groups of particles having different refractive indices. The two or more groups of the particles having different refractive indices preferably include low refractive index particles having a refractive index of less than 1.5 and high refractive index particles having a refractive index of 1.5 or greater.

[0051] In the case where the optical functional layer includes two groups of the particles having different refractive indices, for example, the group of particles having a relatively low refractive index comparing between the two groups of the particles are referred to as “low refractive index particles”, and the other group of particles having a relatively high refractive index are referred to as “high refractive index particles.” In the case where the optical functional layer includes three or more groups of the particles having different refractive indices, the group of the particles having the highest refractive index are referred to as “high refractive index particles,” and the group of the particles having the lowest refractive index are referred to as “low refractive index particles.”

[0052] In the case where the high refractive index particles and the low refractive index particles are mixed in the optical functional layer, the refractive index of the optical functional layer is increased by increasing the concentration of the high refractive index particles in each layer region of the optical functional layer. Similarly, the refractive index of the optical functional layer is decreased by increasing the concentration of the low refractive index particles in each layer region of the optical functional layer.

[0053] -Low refractive index particles- The refractive index of the low refractive index particles is less than 1.5. The low refractive index particles are not particularly limited as long as the low refractive index particles have the refractive index of less than 1.5, and may be appropriately selected according to the intended purpose. Examples of the low refractive index particles include polymer particles, silica particles, oxide particles, particles in which voids are formed by externally applying energy, and the like.

[0054] A polymer of the polymer particles is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the polymer include crosslinked acrylics and the like.

[0055] An oxide in the oxide particles is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the oxide include zirconia, titanium oxide, and the like.

[0056] A structure of each low refractive index particle is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the low refractive index particles may have a hollow structure or a porous structure. A porosity of the low refractive index particles having a hollow structure or a porous structure is not particularly limited, and may be appropriately selected according to the intended purpose. In view of reduction in a refractive index of the optical functional layer and increase in durability of the low refractive index particles themselves, the porosity of the low refractive index particles is preferably 40% or greater and 80% or less.

[0057] A method for measuring the porosity of the low refractive index particles is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the porosity can be measured according to mercury porosimetry using a Poremaster (produced by Anton Paar GmbH), a gas adsorption method using a gas-adsorption specific surface area / pore size distribution analyzer (produced by Seika Digital Image CORPORATION), a relationship between an apparent density D1 and a true density D0 of the particles, or the like.

[0058] One example of a method for estimating the porosity of the particles based on the relationship between apparent density D1 and true density D0 of the particles will be described. First, a volumetric flask having a volume of 100 cm3is charged with approximately 30 cm3of the particles, and a mass of the particles is accurately weighed. Next, the volumetric flask charged with the particles is precisely filled with isopropanol up to the marked line with care not to include any air bubbles. A mass of the isopropanol added to the volumetric flask is accurately weighed. An apparent density D1(g / cm3) of the particles is calculated according to the following equation (I).

[0059]

[0060] Next, a volumetric flask having a volume of 100 cm3is charged with approximately 10 g of crushed particles, and a mass of the crushed pieces is accurately weighed. In the similar manner as in the measurement of the apparent density D1, isopropanol is added to the volumetric flask, and a mass of isopropanol is accurately weighed. A true density D0 (g / cm3) of the particles is calculated according to the following equation (II). Note that pores are not considered as portions constituting the particles in the calculation of the true density D0.

[0061]

[0062] A porosity (%) of the particles is calculated from the apparent density D1 and true density D0 of the particles according to the following equation (III).

[0063]

[0064] Shapes of the low refractive index particles are not particularly limited, and may be appropriately selected according to the intended purpose. For example, the shapes of the low refractive index particles may be regular shapes or irregular shapes. Examples of the regular shapes of the low refractive index particles include spherical shapes, plate shapes, flake shapes, rod shapes, column shapes, needle shapes, branched shapes, sponge shapes, angular shapes, oval shapes, and the like.

[0065] The size of the low refractive index particles is not particularly limited, and may be appropriately selected according to the intended purpose. As the size of the low refractive index particles, the average primary particle diameter of the low refractive index particles is preferably 1 nm or greater and 200 nm or less, and more preferably 10 nm or greater and 100 nm or less. For example, the size of the low refractive index particles based on the average primary particle diameter is preferably 100 nm or less in view of an excellent effect of reducing haze. Note that the size of the particles may be appropriately adjusted according to the intended use.

[0066] A method for measuring the particle diameters of the low refractive index particles is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the particle diameters of the low refractive index particles can be measured by a dynamic laser scattering particle size distribution analyzer (VASCO, produced by CORDOUAN Technologies), a laser diffraction particle size distribution analyzer (Partica LA-960V2, produced by HORIBA, Ltd.), cross-section observation with a Schottky field emission scanning electron microscope (Schottky FE-SEM), or the like.

[0067] -High refractive index particles- The refractive index of the high refractive index particles is 1.5 or greater. The high refractive index particles are not particularly limited as long as the high refractive index particles have the refractive index of 1.5 or greater, and may be appropriately selected according to the intended purpose. For example, the high refractive index particles are preferably oxide particles including at least one selected from the group consisting of aluminum, zirconium, titanium, zinc, germanium, indium, tin, antimony, and cerium.

[0068] A structure of each high refractive index particle is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the high refractive index particles may have a hollow structure or a porous structure. A porosity of the high refractive index particles having a hollow structure or a porous structure is not particularly limited, and may be appropriately selected according to the intended purpose. In view of increase in a refractive index of a resultant optical functional layer, precise adjustment of the refractive index, and durability of the high refractive index particles, the porosity of the high refractive index particles is preferably 10% or greater and 40% or less.

[0069] A method for measuring the porosity of the high refractive index particles is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the porosity can be measured according to mercury porosimetry using a Poremaster (produced by Anton Paar GmbH), a gas adsorption method using a gas-adsorption specific surface area / pore size distribution analyzer (produced by Seika Digital Image CORPORATION), a relationship between an apparent density D1 and a true density D0 of the particles, or the like.

[0070] Shapes of the high refractive index particles are not particularly limited, and may be appropriately selected according to the intended purpose. For example, the shapes of the high refractive index particles may be regular shapes or irregular shapes. Examples of the regular shapes of the high refractive index particles include spherical shapes, plate shapes, flake shapes, rod shapes, column shapes, needle shapes, branched shapes, sponge shapes, angular shapes, oval shapes, and the like.

[0071] A size of the high refractive index particles is not particularly limited, and may be appropriately selected according to the intended purpose. As the size of the high refractive index particles, the average primary particle diameter of the high refractive index particles is preferably 1 nm or greater and 200 nm or less, and more preferably 10 nm or greater and 100 nm or less. For example, the size of the high refractive index particles based on the average primary particle diameter is preferably 100 nm or less in view of an excellent effect of reducing haze. Note that the size of the particles may be appropriately adjusted according to the intended use.

[0072] A method for measuring the particle diameters of the high refractive index particles is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the particle diameters of the high refractive index particles can be measured by a dynamic laser scattering particle size distribution analyzer (VASCO, produced by CORDOUAN Technologies), a laser diffraction particle size distribution analyzer (Partica LA-960V2, produced by HORIBA, Ltd.), cross-section observation with a Schottky field emission scanning electron microscope (Schottky FE-SEM), or the like.

[0073] As the particles, appropriately produced particles may be used, or a commercially available product may be used. The commercially available product of the low refractive index particles is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the commercially available product under a product name include TECHPOLYMER (produced by Sekisui Kasei Co., Ltd.), TMPS (produced by Taiyo Kagaku Co., Ltd.), and the like. A commercially available product of the high refractive index particles is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the commercially available product of the high refractive index particles under a product name include ZIRCOSTAR (produced by NIPPON SHOKUBAI CO., LTD.), a titanium oxide nanoparticle dispersion liquid (produced by DAIHACHI CHEMICAL INDUSTRY CO., LTD.), and the like.

[0074] One embodiment of the optical component of the present disclosure will be described with reference to drawings. However, the present disclosure is not limited to the following embodiment in any way.

[0075] In the drawings, the same constituent components are denoted by the same reference numerals, and redundant description may be omitted. The number, position, shape, and the like of the constituent components are not limited to those in the present embodiment, and may be any number, position, shape, and the like that are preferable for implementing the present disclosure.

[0076] As one embodiment of the optical component of the present disclosure, there is an embodiment in which a refractive index of the optical functional layer decreases in a direction from a layer region closest to the substrate to a layer region present at the outermost surface of the optical functional layer. The details will be described with reference to Fig. 1A.

[0077] (Fig. 1A) Fig. 1A is a schematic cross-sectional view illustrating the optical component according to one embodiment of the present disclosure. The optical component 101 includes a substrate 1 and an optical functional layer 20 disposed over the substrate 1. The optical functional layer 20 includes particles 31 and a resin 32. The optical functional layer 20 includes multiple layer regions 21 to 27 that are defined by dividing the optical functional layer 20 by 100 nm from the interface between the substrate 1 and the optical functional layer 20 in the thickness direction of the optical functional layer 20. More specifically, the optical functional layer 20 includes a first layer region 21 on the substrate 1, a second layer region 22 on the first layer region 21, a third layer region 23 on the second layer region 22, a fourth layer region 24 on the third layer region 23, a fifth layer region 25 on the fourth layer region 24, a sixth layer region 26 on the fifth layer region 25, and a seventh layer region 27 on the sixth layer region 26.

[0078] Although the optical functional layer 20 is represented by the seven layer regions in Fig. 1A for convenience, the number of layer regions in the optical functional layer 20 is not particularly limited, and may be appropriately set according to the intended use of the optical component or a degree of modulation of the refractive index.

[0079] For example, in the case where it is desired to modulate the refractive index of the optical functional layer from 1.2 to 1.5 by changing the refractive index between the layer regions in the optical functional layer by 0.01, the number of the layer regions in the optical functional layer is preferably 30 or greater and 60 or less. In this case, when the number of the layer regions in the optical functional layer is 60 or less, problems, such as insufficient cohesiveness within the optical functional layer, and low productivity due to a long curing time, can be avoided.

[0080] For example, in the case where it is desired to modulate the refractive index of the optical functional layer from 1.2 to 1.5 by changing the refractive index between the layer regions in the optical functional layer by 0.1, the number of the layer regions in the optical functional layer is preferably 3 or greater and 7 or less. In this case, when the number of the layer regions of the optical functional layer is 7 or less, problems, such that the particles are not evenly distributed in the optical functional layer and a desired gradient of the refractive index cannot be formed, can be avoided.

[0081] In the optical component of the present disclosure, a difference in refractive index between at least one pair of the layer regions in contact with each other in the optical functional layer is greater than 0 and 0.1 or less. In Fig. 1A, the difference in refractive index between the first layer region 21 and the second layer region 22 in contact with the first layer region 21 is greater than 0 and 0.1 or less. Similarly, the difference in refractive index between the second layer region 22 and the third layer region 23 in contact with the second layer region 22 is greater than 0 and 0.1 or less. Similarly, the difference in the refractive index between the third layer region 23 and the fourth layer region 24, the difference in the refractive index between the fourth layer region 24 and the fifth layer region 25, the difference in the refractive index between the fifth layer region 25 and the sixth layer region 26, and the difference in the refractive index between the sixth layer region 26 and the seventh layer region 27 are all greater than 0 and 0.1 or less.

[0082] The liquid composition for forming the first layer region 21 in Fig. 1A is prepared to have the lower concentration of the particles 31 than the concentrations of the particles 31 in the liquid compositions for other layer regions 22 to 27. Thus, the refractive index of the first layer region 21 obtained by curing becomes higher than the refractive indices of other layer regions 22 to 27. The concentration of the particles 31 in the liquid composition for forming the second layer region 22 is adjusted so that a difference in refractive index between the second layer region 22 obtained by curing and the first layer region 21 becomes greater than 0 and 0.1 or less, and the refractive index of the second layer region 22 is lower than the refractive index of the first layer region 21. The same is applied to the subsequent layer regions 22 to 27. As a result, the optical component 101, in which the refractive index decreases in the direction from the interface between the substrate 1 and the optical functional layer 20, i.e., the interface between the substrate 1 and the first layer region 21, to the seventh layer region 27 present at the outermost surface of the optical functional layer 20, is obtained.

[0083] Since the optical component has the above configuration, the reflectance can be set at a constant value without depending on a wavelength range or an angle of incident light. Specifically, the wavelength dependency of the optical component can be minimized.

[0084] As another embodiment of the optical component of the present disclosure, there is an embodiment in which the refractive index is increased from the layer region of the optical functional layer that is in contact with the substrate to the layer region of the optical functional layer at the outermost surface of the optical functional layer. The details are described with reference to Fig. 1B.

[0085] (Fig. 1B) Fig. 1B is a schematic cross-sectional view illustrating the optical component according to another embodiment of the present disclosure. The optical component 102 includes a substrate 1 and an optical functional layer 20 disposed over the substrate 1. The optical component 102 has the same configuration as the optical component 101 of Fig. 1A, except that the refractive index increases from the layer region of the optical functional layer that is in contact with the substrate to the layer region of the optical functional layer present at the outermost surface of the optical functional layer. Thus, redundant description will be omitted.

[0086] In the case where the optical component of the present disclosure includes particles, the particles are preferably distributed at the interface between the layer regions in contact with each other in the optical functional layer. The details will be described with reference to Figs. 2A and 2B.

[0087] (Figs. 2A and 2B) Fig. 2A is a schematic cross-sectional view illustrating the optical component according to another embodiment of the present disclosure. Fig. 2B is a schematic enlarged view of the interface between the layer regions in contact with each other in the optical functional layer of Fig. 2A.

[0088] A mechanism for changing a refractive index between the layer regions 21 to 27 in contact with one another in the optical functional layer 20 is as follows. For example, when a liquid composition is applied onto the layer region 21 to form a layer region 22, the resin 32 present at the surface of the layer region 21 serving as a lower layer is dissolved. When the liquid composition applied on the layer region 21 is cured in the above-described state, the particles 31 are distributed at the interface between the layer regions 21 and 22 in contact with each other. Since the optical component has the above configuration, the refractive index in the thickness direction of the substrate 1 can be more gradually modulated to achieve the desired distribution of the refractive index so that the refractive index can be highly precisely controlled.

[0089] In each of the layer regions 21 to 27 of the optical functional layer, the particles 31 are preferably evenly distributed in the thickness direction of each layer region of the optical functional layer. When the particles 31 are evenly distributed in the thickness direction of each layer region of the optical functional layer, the particles 31 absorb and disperse the stress applied to the optical functional layer, and therefore the strength of the entire optical functional layer can be improved.

[0090] As another embodiment of the optical component of the present disclosure, there is an embodiment in which the optical functional layer includes regions having different refractive indices in a planar direction of the optical functional layer as illustrated in Fig. 4A, which will be described later.

[0091] In the present specification, the phrase “state in which the particles are evenly distributed” refers to that the abundance of the particles in an arbitrary section of one layer region is even in the thickness direction of the optical functional layer and in the direction intersecting the thickness direction of the optical functional layer, or a state in which a variation in the abundance is small.

[0092] The phrase “state in which the particles are not evenly distributed” refers to, for example, a case where the particles are locally distributed in a certain location of one layer region in the thickness direction of the optical functional layer and in the direction intersecting the thickness direction of the optical functional layer. For example, the phrase “state in which the particles are not evenly distributed” refers to a case where the particles are locally distributed in the upper portion, the center portion, the lower portion, or any combination of the foregoing of one layer region in the thickness direction of the optical functional layer.

[0093] A method for confirming the state of the particles in the optical functional layer is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the state of the particles in the optical functional layer can be confirmed by calculating a proportion of the particles by image processing of image data of multiple points of the optical functional layer in the thickness direction of the substrate and in the direction intersecting the thickness direction of the substrate, which is acquired by two-dimensional cross-section observation using a Schottky field emission scanning electron microscope (Schottky FE-SEM), or by processing a sample by a focused ion beam device to expose a cross-section, and performing a three-dimensional cross-section observation using a scanning electron microscope (FIB / SEM cross beam device NVision40, produced by Carl ZEISS (SII-NT)).

[0094] The optical functional layer of the optical component of the present disclosure preferably includes two or more groups of particles having different refractive indices.

[0095] In the optical component of the present disclosure, the low refractive index particles are preferably exposed at the outermost surface of the optical functional layer. The optical component having the above configuration is desirable because the refractive index at the surface of the optical component can be further reduced.

[0096] A method for exposing the low refractive index particles at the outermost surface of the optical functional layer is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the method include: a method in which the low refractive index particles (or a liquid composition including the low refractive index particles) are applied onto the outermost surface of the optical functional layer; a method in which part of the pre-formed optical functional layer including the low refractive index particles is abraded to expose the low refractive index particles; and the like.

[0097] A method for confirming the configuration of the optical component of the present disclosure is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the configuration of the optical component can be confirmed by the following method.

[0098] The presence of the substrate and the optical functional layer in the optical component of the present disclosure can be confirmed by evaluating the reflectance of the optical component in a visible spectral region (380 nm to 780 nm) using a spectrophotometer (V-770, produced by JASCO Corporation) with an angle of incidence being set at 5 degrees.

[0099] A method for confirming whether the particles are distributed at the interface between each pair of the layer regions in contact with each other in the optical functional layer is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the distribution of the particles can be confirmed by stacking layer regions using fluorescent particles as the particles, and performing mapping of the fluorescent particles by time-of-flight secondary ion mass spectrometry (TOF. SIMS 5, produced by ION-TOF). Moreover, the distribution of the particles can be confirmed by observing whether the particles are distributed on the divided lines dividing off corresponding regions in the thickness direction through two-dimensional cross-section observation using a Schottky field emission scanning electron microscope (Schottky FE-SEM), or by processing a sample by a focused ion beam device to expose a cross-section, and performing a three-dimensional cross-section observation using a scanning electron microscope (FIB / SEM cross beam device NVision40, produced by Carl ZEISS (SII-NT)).

[0100] (Average reflectance of optical component) The reflectance of the optical component is not particularly limited, and may be appropriately selected according to the intended purpose. In the case where the optical component is adjusted to have low reflectance, the average reflectance in the visible spectral region (380 nm to 780 nm) is set to less than 5.0%. In the case where the optical component is adjusted to have low reflectance, the average reflectance in the visible spectral region (380 nm to 780 nm) is preferably 0.5% or greater and less than 5.0%.

[0101] In the case where the optical component is adjusted to have high reflectance, the average reflectance in the visible spectral region (380 nm to 780 nm) is preferably 7.0% or greater.

[0102] The reflection of the optical component is measured by a spectrophotometer (e.g., V-770, produced by JASCO Corporation) with an angle of incidence being set to 5 degrees under the conditions described in Examples.

[0103] (Wavelength dependency of optical component) The wavelength dependency of the optical component is not particularly limited, and may be appropriately selected according to the intended purpose. As the wavelength dependency, a difference between the maximum reflectance and the minimum reflectance is preferably 5% or less, where the maximum reflectance is a maximum reflectance of the optical component in the visible spectral region measured with an angle of incidence of 5 degrees, and the minimum reflectance is a minimum reflectance of the optical component in the visible spectral region measured with an angle of incidence of 5 degrees.

[0104] In the case where the optical component is adjusted to have low reflectance, the absolute value of the wavelength dependency of the optical component is preferably 0.5% or greater and 3.0% or less, and more preferably less than 0.5%. In the case where the optical component is adjusted to have high reflectance, the absolute value of the wavelength dependency of the optical component is preferably 0.5% or greater and 5.0% or less, and more preferably less than 0.5%.

[0105] The wavelength dependency of the optical component is measured by a spectrophotometer (e.g., V-770, produced by JASCO Corporation) with an angle of incidence being set to 5 degrees under the conditions described in Examples.

[0106] (Average transmittance of optical component) The average transmittance of the optical component is not particularly limited, and may be appropriately selected according to the intended purpose. In the case where the optical component is adjusted to have a low refractive index, the average transmittance at an angle of incidence of 0 degrees is preferably 70% or greater, and more preferably 95% or greater. In the case where the optical component is adjusted to have high refractive index, the average transmittance at an angle of incidence of 0 degrees is preferably 70% or greater, and more preferably 85% or greater.

[0107] The transmittance of the optical component is measured by a spectrophotometer (e.g., V-770, produced by JASCO Corporation) with an angle of incidence being set to 0 degrees under the conditions described in Examples.

[0108] (Haze value of optical component) The haze value of the optical component is not particularly limited and may be appropriately selected according to the intended purpose. In the case where the optical component is adjusted to have low reflectance, the haze value is preferably less than 30%, and more preferably less than 1.0%. In the case where the optical component is adjusted to have high reflectance, the haze value is preferably less than 30%, and more preferably less than 10%.

[0109] The haze value of the optical component is measured by a haze meter (e.g., NDH 5000, produced by DENSHOKU INDUSTRIES Co., Ltd.) according to JIS-K-7136:2000 (ISO 14782 : 1999).

[0110] The optical component of the present disclosure can control the reflectance as desired, has excellent film strength, and has less wavelength dependency of reflectance owing to the above configuration of the optical component. The optical component of the present disclosure preferably further has excellent adhesion between layer regions of the optical functional layer.

[0111] (Method for producing optical component) The method for producing the optical component of the present disclosure includes a film formation process, a film curing process, and an optical functional layer formation process, and may further include other processes.

[0112] An optical component production apparatus associated with the present disclosure includes a film formation device, a film curing device, and an optical functional layer formation mechanism, and may further include other mechanisms, as necessary. The method for producing the optical component of the present disclosure can be suitably performed by the optical component production apparatus.

[0113] The method for producing the optical component of the present disclosure and the optical component production apparatus of the present disclosure can suitably produce the optical component of the present disclosure.

[0114] <Film formation process> The film formation process is a process in which a liquid composition including particles is discharged onto a substrate to form a film. The film formation device is a device that discharges a liquid composition including particles, a resin, or both particles and a resin to form a film. The film formation process is suitably performed by the film formation device.

[0115] In the below-described optical functional layer formation process, the film formation process and the below-described film curing process are repeated to form an optical functional layer having a uniform thickness. The optical functional layer formation process includes performing the film formation process two or more times with the liquid compositions having different concentrations of the particles so that, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less.

[0116] A thickness of a film formed by the film formation process is preferably 1 nm or greater and 200 nm or less, and more preferably 10 nm or greater and 100 nm or less. Since the thickness of the film formed by the film formation process is 1 nm or greater and 200 nm or less, the difference in the layer regions of the optical functional layer can fall within a preferable range.

[0117] A film formation method is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the film formation method include dispensing, spin coating, and inkjet printing, which are wet methods, and the like. Among the above film formation method, inkjet printing is preferably used in view of high efficiency in use of the materials, reduction in cost because no printing plate is required, and the like.

[0118] Examples of the inkjet printing include: a charge control method in which a liquid composition is discharged using electrostatic attraction; a drop-on-demand method (pressure pulse method) using vibration pressure of a piezoelectric element; an acoustic inkjet printing in which an electric signal is converted into an acoustic beam, the liquid composition is irradiated with the acoustic beam, and the liquid composition is discharged using the radiation pressure; a thermal inkjet (Bubble Jet (registered trademark)) method in which a liquid composition is heated to generate air bubbles, and the pressure caused by the generated air bubbles is used; and the like.

[0119] Droplets of the liquid composition are controlled mainly by a print head. In the case of the thermal inkjet printing, an amount of droplets to be discharged can be controlled with a structure of the print head. Specifically, a desired size of a droplet can be discharged by varying sizes of an ink chamber, a heating unit, and a nozzle. Even in the case of the thermal inkjet printing, multiple sizes of droplets can be discharged by providing multiple print heads having different sizes of the heating units or nozzles.

[0120] In the case of the drop-on-demand method using the piezoelectric element, it is also possible to change an amount of droplets to be discharged due to the structure of the print head in the similar manner as the thermal, inkjet printing but it is also possible to discharge different sizes of droplets from the print heads of the same structure by controlling a waveform of a driving signal for driving the piezoelectric element.

[0121] In the case where the liquid composition is discharged by the inkjet printing, a discharge amount of the liquid composition is not particularly limited, and may be appropriately selected according to the intended purpose. In view of resolution and productivity, the discharge amount is preferably 1 pL or greater and 100 pL or less.

[0122] In the case where the liquid composition is discharged by inkjet printing, two or more liquid compositions having different refractive indices are used so that the optical functional layer cured in the optical functional layer formation process includes two or more cured products having different refractive indices. In the film formation process, two liquid compositions having different refractive indices may be used. In the case where two liquid compositions having different refractive indices are used, a liquid composition that can form a cured product having a relatively low refractive index compared to a cured product of the other liquid composition is referred to as a “low refractive index liquid composition” in the present specification. In the case where two liquid compositions having different refractive indices are used, moreover, a liquid composition that can form a cured product having a relatively high refractive index compared to a cured product of the other liquid composition is referred to as a “high refractive index liquid composition.” In the case where three or more liquid compositions having different refractive indices are used in the film formation process, a liquid composition that can form a cured product having the highest refractive index is referred to as a “high refractive index liquid composition” and a liquid composition that can form a cured product having the lowest refractive index is referred to as a “low refractive index liquid composition” in the present specification.

[0123] In the present specification, the “high refractive index liquid composition” and the “low refractive index liquid composition” may be simply referred to as a “liquid composition” when the high refractive index liquid composition and the low refractive index liquid composition are not distinguished from each other.

[0124] In the case where the liquid compositions are discharged by inkjet printing, the liquid compositions may be discharged while changing amounts of two or more liquid compositions having different refractive indices in the film formation process. Thus, optical components having various configurations can be produced.

[0125] The discharge amount of each liquid composition per discharge operation is not particularly limited, and may be appropriately selected according to the intended purpose. In view of resolution and productivity, the discharge amount of each liquid composition is preferably 0.1 pL or greater and 100 pL or less, and more preferably 1 pL or greater and 30 pL or less. In the case where the liquid composition is discharged by inkjet printing, the discharge amount per discharge operation refers to a total amount of the liquid composition discharged from multiple holes of an inkjet head by one discharge operation.

[0126] For example, the discharge amount of the high refractive index liquid composition per discharge operation may be set to be large (e.g., 5 pL), and the discharge amount of the low refractive index liquid composition per discharge operation may be set to be small (e.g., 2 pL). Alternatively, the discharge amount of the high refractive index liquid composition per discharge operation may be set to be small (e.g., 2 pL), and the discharge amount of the low refractive index liquid composition per discharge operation may be set to be large (e.g., 5 pL).

[0127] In the case where the liquid composition is discharged by inkjet printing, the resolution is not particularly limited, and may be appropriately selected according to the intended purpose. For changing a refractive index in the direction intersecting the thickness direction of the substrate, the resolution is preferably 20 dpi or greater.

[0128] The film formation process preferably includes discharge of the two or more liquid compositions having different refractive indices onto the substrate by inkjet printing to form a print pattern in the direction intersecting the thickness direction of the substrate. The formation of the print pattern is achieved by discharging the liquid compositions in a manner such that one liquid composition and another liquid composition having a different refractive index to the one liquid composition are in contact with each other in the direction intersecting the thickness direction of the substrate.

[0129] The embodiment in which one liquid composition and another liquid composition having a refractive index different from the one liquid composition are in contact with each other is preferably an embodiment in which a droplet of one liquid composition and a droplet of another liquid composition having a different refractive index to the one liquid composition are in contact with each other.

[0130] More specifically, the formation of the print pattern can be achieved in the following manner. When a droplet of one liquid composition is discharged on the substrate, followed by discharging a droplet of another liquid composition having a refractive index different from the one liquid composition, the droplet of another liquid composition is discharged in a manner such that a center of the droplet of another liquid composition is located outside the outline of the droplet of the one liquid composition so that the droplets of the two or more liquid compositions having different refractive indices are arranged to be in contact with each other.

[0131] In the present specification, the phrase “a droplet of one liquid composition and a droplet of another liquid composition having a refractive index different from the one liquid composition are in contact with each other in the direction intersecting the thickness direction of the substrate” means that part of a discharged droplet of one liquid composition is in contact with part of a droplet of another liquid composition. As a result of part of a discharged droplet of one liquid composition coming into contact with part of a droplet of another liquid composition, the liquid compositions may be mixed to the extent that the refractive indices of the reflective liquid compositions are not changed. In the case where the above process is included, it is possible to form the optical functional layer illustrated in Fig. 4A. In Fig. 4A, the dark region (with a higher concentration of dots) of the optical functional layer indicates that a ratio of the high refractive index liquid composition to a total amount of the discharged liquid compositions is higher than the ratio in a pale (with a lower concentration of dots) of the optical functional layer.

[0132] Fig. 3A is a schematic top view illustrating one example of a state of droplets of the liquid composition at the time of landing by scanning once in the film formation process of the method for producing the optical component according to one embodiment of the present disclosure. Fig. 3B is a schematic top view illustrating another example of the state of droplets of the liquid composition at the time of landing by scanning once in formation of a print pattern in the film formation process.

[0133] Fig. 3A illustrates a state in which an outline of a droplet of one liquid composition 42 and an outline of a droplet of another liquid composition 41, which is in contact with the droplet of the liquid composition 42, are in contact with each other, and a center X2 of the droplet of the liquid composition 41 is located outside the outline of the droplet of the liquid composition 42.

[0134] Fig. 3B illustrates a state in which an outline of a droplet of one liquid composition 42 and an outline of a droplet of another liquid composition 41, which is in contact with the droplet of the liquid composition 42, overlap each other, and a center X2 of the droplet of the liquid composition 41 is located outside the edge of the droplet of the liquid composition 42.

[0135] In the present specification, a center of a droplet of the liquid composition can be determined by the following method. After the film formation process, a top view of the droplets of the liquid composition is captured, and an outline of each droplet of the liquid composition is determined by image processing. Next, in the case where the determined outline is an oval, a major axis of the oval and a minor axis of the oval are determined. A cross point of the major axis and the minor axis is determined as a center of the droplet of the liquid composition. In the case where the determined outline is a true circle, a point where perpendicular bisectors of three points arbitrarily selected on the outline intersect is set as a center of the droplet of the liquid composition. In the case where the determined outline is an irregular shape, a center of gravity of the droplet can be determined as a center of the droplet. The center of gravity of the droplet having the irregular outline is the intersection of two vertical lines drawn by rotating the droplet about an arbitrary rotation axis.

[0136] As illustrated in Fig. 3B, in the case where an outline of a droplet of one liquid composition 42 and an outline of a droplet of another liquid composition 41 in contact with the droplet of the liquid composition 42 overlap each other, and a center X2 of the droplet of another liquid composition 41 is located outside the outline of the droplet of the liquid composition 42, when a total area of the droplet of the liquid composition 42 or the droplet of the another liquid composition 41 on a top view is determined as 100%, an area of an overlapping part of the droplet of the liquid composition 42 and the droplet of another liquid composition 41 is not particularly limited, and is preferably less than 50%. In the case where a size of the droplet of the liquid composition 42 and a size of the droplet of another liquid composition 41 are different, a total area of the smaller droplet is determined as 100%.

[0137] Next, an optical component according to one embodiment, when formation of a print pattern is performed in a film formation process, will be described through specific examples.

[0138] (Figs 4A and 4B) Fig. 4A is a schematic cross-sectional view illustrating a state after the optical functional layer formation process in the method for producing the optical component according to one embodiment of the present disclosure. Fig. 4B is a schematic top view illustrating print patterns for forming corresponding layers of Fig. 4A.

[0139] As illustrated in Fig. 4A, the optical component 103 includes a substrate 1 and an optical functional layer 20 disposed over the substrate 1. The optical functional layer 20 includes multiple layer regions 21 to 23 obtained by dividing the optical functional layer 20 by 100 nm from the interface between the substrate 1 and the optical functional layer 20 in the thickness direction of the optical functional layer 20. The optical component 103 has the same configuration as the optical component 101 of Fig. 1A, except that the refractive index is changed in the direction intersecting the thickness direction of the optical functional layer 20, and therefore redundant description will be omitted.

[0140] As illustrated in Fig. 4B, in the first layer region 21 and the third layer region 23, the corresponding liquid compositions are deposited on the substrate 1 in a manner such that the refractive index is changed at least in one direction intersecting the thickness direction of the substrate 1.

[0141] Specifically, in the first layer region 21, the liquid compositions are applied so that the proportion of the high refractive index liquid composition 42 is large at the left end side of the first layer region 21 of Fig. 4B. Moreover, the liquid compositions are applied so that the proportion of the low refractive index liquid composition 41 is gradually increased from the left end side to the right end side of the print pattern for forming the first layer region 21 of Fig. 4B. Further, the liquid compositions are applied so that the proportion of the low refractive index liquid composition 41 is large at the right end side of the print pattern for forming the first layer region 21 of Fig. 4B. Thus, in the first layer region 21, the refractive index is relatively low at the right end side compared to the left end side, and the refractive index of the first layer region 21 gradually decreases from the right end side to the left end side.

[0142] The liquid compositions are applied so that the proportion of the low refractive index liquid composition 41 is large at the left end side of the print pattern for forming the third layer region 23 of Fig. 4B. Moreover, the liquid compositions are applied so that the proportion of the high refractive index liquid composition 42 is gradually increased from the left end side to the right end side of the print pattern for forming the third layer region 23 of Fig. 4B. Further, the liquid compositions are applied so that the proportion of the high refractive index liquid composition 42 is large at the right end side of the third layer region 23 of Fig. 4B. As a result, in the third layer region 23, the refractive index is relatively low at the left end side compared to the right end side, and the refractive index of the third layer region 23 gradually increases from the left end side to the right end side.

[0143] In the print pattern for forming the second layer region 22 of Fig. 4B, droplets of the low refractive index liquid composition 41 and droplets of the high refractive index liquid composition 42 are alternately applied so that the droplets of the low refractive index liquid composition 41 and the droplets of the high refractive index liquid composition 42 are alternately in contact with each other (in a checkered pattern). Thus, the refractive index of the entire second layer region 22 is substantially uniform, and is intermediate. The term “intermediate” refers to that the refractive index is approximately the same as the refractive index of the center portion between the right end side and the left end side of the first layer region 21, or the refractive index of the center portion between the right end side and the left end side of the third layer region 23.

[0144] The second layer region 22 having the checkered pattern can be obtained by alternately discharging droplets of the low refractive index liquid composition 41 and droplets of the high refractive index liquid composition 42. Similarly to the first layer region 21 and the third layer region 23, the second layer region 22 may be obtained by applying corresponding liquid compositions to change a refractive index. The optical component having the above configuration can used as, for example, an optical filter that reflects a specific wavelength.

[0145] Note that droplets of the low refractive index liquid composition 41 and droplets of the high refractive index liquid composition 42 may be randomly discharged onto the substrate 1 to form a film.

[0146] The optical component having the above configuration has the refractive index that is changed in the planar direction, and therefore has an effect of reflecting a specific wavelength. Accordingly, the optical component having the above configuration can be suitably adapted as, for example, an optical filter.

[0147] By using two or more liquid compositions having different refractive indices, an optical component with a refractive index being changed in the thickness direction of the optical functional layer, and in the direction intersecting the thickness direction of the optical functional layer can be formed, as illustrated in Fig. 4A. The difference in refractive index between one layer region and another layer region, which is other than the one layer region, in the optical component can be determined from refractive indices of layer regions stacked in a stacking direction of the layer regions of the optical functional layer.

[0148] The phrase “at least one direction intersecting the thickness direction of the substrate” or “at least one planar direction of the optical functional layer” is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the “at least one direction intersecting the thickness direction of the substrate” or “at least one planar direction of the optical functional layer” include a direction from one edge of the optical functional layer to the other edge of the optical functional layer, a direction from an arbitrary position of the optical functional layer to another arbitrary position of the optical functional layer, and the like. Therefore, the start point and the end point of the “at least one direction intersecting the thickness direction of the substrate” or “at least one planar direction of the optical functional layer” can be appropriately selected according to the intended purpose.

[0149] A method for discharging two or more liquid compositions having different refractive indices to change the refractive index at least in one direction intersecting the thickness direction of the substrate include a method in which one liquid composition and another liquid composition having a refractive index different from the one liquid composition are alternately discharged. The method is preferably a method in which droplets of one liquid composition and droplets of another liquid composition having a different refractive index from the one liquid composition are alternately discharged.

[0150] In order to increase adhesion or wettability to the substrate, a primer ink may be applied onto the substrate, the optical functional layer, or both the substrate and the optical functional layer as a pretreatment, a post treatment, or both in the film formation process.

[0151] Examples of the primer ink include a primer ink that includes a polymerizable compound, a polymerization initiator, an organic solvent, a surfactant, and the like.

[0152] The polymerizable compound is not particularly limited, and may be appropriately selected according to the intended purpose. The polymerizable compound preferably includes at least one adhesion promoting component selected from the group consisting of a N-vinyl lactam compound, an acrylamide-based compound, and a N-vinylamide compound.

[0153] The polymerization initiator is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the polymerization initiator include compounds that generate active species, such as radicals and cations, with energy of active energy rays to initiate polymerization of a polymerizable compound (a monomer or an oligomer). As the polymerization initiator, one or more radical polymerization initiators, cationic polymerization initiators, base generators, and the like, which are available in the related art, can be used in combination. Among the above polymerization initiators, a radical polymerization initiator is preferably used.

[0154] The thickness of the applied primer ink is not particularly limited, and may be appropriately set considering a composition of a liquid, desired adhesion performance, desired optical performance, or the like. The thickness of the applied primer ink is preferably 0.1 μm or greater and 5 μm or less, more preferably 0.5 μm or greater and 3 μm or less, and yet more preferably 1 μm or greater and 2 μm or less. When the thickness of the applied primer ink is 0.1 μm or greater, fixability and permeability of the ink are imparted. When the thickness of the applied primer ink is 5 μm or less, drying speed can be shortened after application of the primer ink.

[0155] The physical properties of the primer ink are not particularly limited, and may be appropriately selected according to the intended purpose. For example, the primer ink preferably has the viscosity and the surface tension in the following ranges.

[0156] The viscosity of the primer ink at 25 degrees Celsius is preferably 5 mPa-s (millipascal seconds) or greater and 20 mPa-s (millipascal seconds), and more preferably 5 mPa-s (millipascal seconds) or greater and 15 mPa-s (millipascal seconds) or less in view of desired discharge performance. The viscosity can be measured, for example, by a rotary viscometer (Viscometer TVE-25L, produced by Tokyo Garasu Kikai Co., Ltd.), a rheometer (MCR302, produced by Anton Paar GmbH), or the like.

[0157] The surface tension of the primer ink is not particularly limited, and may be appropriately selected according to the intended purpose. The surface tension of the primer ink is preferably 10 mN / m or greater, more preferably 20 mN / m or greater. In addition, the surface tension of the primer ink is preferably 40 mN / m or less, and more preferably 30 mN / m or less. When the surface tension of the primer ink is 10 mN / m or greater, a split of a discharged droplet can be avoided. When the surface tension of the primer ink is 40 mN / m or less, problems such that droplets are not easily leveled, and homogeneousness of a coating film is impaired can be avoided.

[0158] A method for measuring the surface tension of the primer ink is not particularly limited, and may be appropriately selected according to the intended purpose. The surface tension of the primer ink can be measured, for example, by a surface tensiometer (DY-300, produced by Kyowa Interface Science Co., Ltd.).

[0159] As the primer ink, an appropriately prepared primer ink may be used, or a commercially available product may be used. Examples of the commercially available product of the primer ink under a product name include PR100 (produced by MIMAKI ENGINEERING CO., LTD.) and the like.

[0160] <<Liquid composition>> Next, a liquid composition used in a film formation process will be described. The liquid composition includes particles, and may further include a solvent and other components, as necessary. The refractive index of the optical functional layer of the present disclosure can be adjusted according to a type or amount, or both of the particles included in the liquid composition. As the particles, the particles described in the section of <<Particles>> in (Optical component) can be used.

[0161] In the liquid composition of the present disclosure, high refractive index particles and low refractive index particles may be appropriately mixed so that a resultant optical functional layer has a desired refractive index.

[0162] In the case where the liquid composition including the mixture of the high refractive index particles and the low refractive index particles is used, the increase of the concentration of the high refractive index particle in the liquid composition leads to increase in the refractive index of the liquid composition. Similarly, the increase of the concentration of the low refractive index particle in the liquid composition leads to decrease in the refractive index of the liquid composition.

[0163] A method for measuring the refractive index of the liquid composition is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the method include a method in which a corresponding liquid composition is applied onto an arbitrary substrate by spin coating to have a film thickness of 100 nm, and a refractive index of the produced film is measured by a spectroscopic ellipsometer M-2000 (produced by J.A. Woollam Japan).

[0164] The liquid composition is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the liquid composition may be a curable liquid composition or a plastic liquid composition. The liquid composition is preferably a curable liquid composition.

[0165] The liquid composition may have a composition that foams during a film curing process to form air cells in a resultant film.

[0166] <<<Solvent>>> The solvent is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the solvent is preferably a solvent that allows the other constituent components to be dissolved or dispersed, can easily achieve homogeneousness in the film formation process or in the film curing process, has excellent liquid storage stability, and has appropriate saturated vapor pressure. Specifically, in view of desired drying, the solvent is preferably a solvent having a boiling point of 50 degrees Celsius or higher and 300 degrees Celsius or lower, and more preferably having a boiling point of 100 degrees Celsius or higher and 200 degrees Celsius or lower at ambient pressure and ambient temperature for adjusting a drying speed.

[0167] Examples of the solvent having a boiling point of lower than 100 degrees Celsius include: hydrocarbons, such as hexane (boiling point: 68.7 degrees Celsius), heptane (boiling point: 98.4 degrees Celsius), cyclohexane (boiling point: 80.7 degrees Celsius), and benzene (boiling point: 80.1 degrees Celsius); halogenated hydrocarbons, such as dichloromethane (boiling point: 39.8 degrees Celsius), chloroform (boiling point: 61.2 degrees Celsius), carbon tetrachloride (boiling point: 76.8 degrees Celsius), 1,2-dichloroethane (boiling point: 83.5 degrees Celsius), and trichloroethylene (boiling point: 87.2 degrees Celsius); ethers, such as diethyl ether (boiling point: 34.6 degrees Celsius), diisopropyl ether (boiling point: 68.5 degrees Celsius), dipropyl ether (boiling point: 90.5 degrees Celsius), and tetrahydrofuran (boiling point: 66 degrees Celsius); esters, such as ethyl formate (boiling point: 54.2 degrees Celsius), methyl acetate (boiling point: 57.8 degrees Celsius), ethyl acetate (boiling point: 77.1 degrees Celsius), and isopropyl acetate (boiling point: 89 degrees Celsius); ketones, such as acetone (boiling point: 56.1 degrees Celsius), and 2-butanone (boiling point: 79.6 degrees Celsius); alcohols, such as methanol (boiling point: 64.5 degrees Celsius), ethanol (boiling point: 78.3 degrees Celsius), 2-propanol (boiling point: 82.4 degrees Celsius), and 1-propanol (boiling point: 97.2 degrees Celsius); cyano compounds, such as acetonitrile (boiling point: 81.6 degrees Celsius), and pripionitrile (boiling point: 97.4 degrees Celsius); carbon disulfide (boiling point: 46.2 degrees Celsius); and the like.

[0168] Among the above solvents, cellosolves, ketones, esters, ethers, and alcohols are preferably used.

[0169] Examples of the solvent having a boiling point of 100 degrees Celsius or higher include propylene glycol monomethyl ether (boiling point: 120.0 degrees Celsius), octane (boiling point: 125.7 degrees Celsius), toluene (boiling point: 110.6 degrees Celsius), xylene (boiling point: 138 degrees Celsius), tetrachloroethylene (boiling point: 121.2 degrees Celsius), chlorobenzene (boiling point: 131.7 degrees Celsius), dioxane (boiling point: 101.3 degrees Celsius), dibutylether (boiling point: 142.4 degrees Celsius), isobutyl acetate (boiling point: 118 degrees Celsius), cyclohexanone (boiling point: 155.7 degrees Celsius), 2-methyl-4-pentanone (boiling point: 115.9 degrees Celsius), 1-butanol (boiling point: 117.7 degrees Celsius), N,N-dimethylformamide (boiling point: 153 degrees Celsius), N,N-dimethylacetoamide (boiling point: 166 degrees Celsius), dimethyl sulfoxide (boiling point: 189 degrees Celsius), and the like.

[0170] Among the above solvents, cellosolves, ketones, esters, ethers, and alcohols are preferably used.

[0171] An amount of the solvent is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the solvent is preferably added so that the solid content of the liquid composition becomes 2 percent by mass or greater and 30 percent by mass or less, more preferably 3 percent by mass or greater and 20 percent by mass or less, and yet more preferably 5 percent by mass or greater and 15 percent by mass or less. By adding the solvent so that the solid content of the liquid composition becomes 2 percent by mass or greater, problems such as a long drying time and an uneven film thickness can be avoided. By adding the solvent so that the solid content of the liquid composition becomes 30 percent by mass or less, problems, such as uneven distribution of particles, uneven coating due to a small coating amount, and the like, can be avoided.

[0172] As the solvent, an appropriately prepared solvent may be used, or a commercially available product may be used. The commercially available product of the solvent is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the commercially available product of the solvent under a product name include propylene glycol monomethyl ether (produced by KANTO CHEMICAL CO., LTD.), methylethylketone (produced by KANTO CHEMICAL CO., LTD.), propylene glycol monomethyl ether acetate (produced by KANTO CHEMICAL CO., LTD.), and the like.

[0173] <<<Other components>>> Other components included in the liquid composition are not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the other components include a resin, a crosslinking agent, a photopolymerization initiator (may be simply referred to as an “initiator” or “photo initiator”), a photosensitizer, a surfactant, a rheology modifier, an antioxidant, an antifungal agent, and the like.

[0174] -Resin- The resin is not particularly limited, and may be appropriately selected according to the intended purpose. The resin is preferably a resin that has good compatibility with other constituent components, and can allow the particles to be dispersed. Specific examples of the resin include non-curing resins that do not require a curing process, curable resins that require a curing process, and the like.

[0175] --Non-curing resin-- The non-curing resins are classified into low refractive index resins and high refractive index resins according to a refractive index.

[0176] ---Low refractive index resin--- The refractive index of the low refractive index resin is not particularly limited, and may be appropriately selected according to the intended purpose. The refractive index of the low refractive index resin is less than 1.5. The low refractive index resin is not particularly limited, as long as the low refractive index resin has a refractive index of less than 1.5, and may be appropriately selected according to the intended purpose. Examples of the low refractive index resin include (meth)acrylic resins (e.g., methyl polymethacrylate), siloxane resins, norbornene resins (e.g., polynorbornene) and the like. The above resins may be used alone or in combination.

[0177] In view of reduction in a refractive index, the low refractive index resin may include a fluorine-containing resin. The fluorine-containing resin is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the fluorine-containing resin include a tetrafluoroethylene-perfluorodioxole copolymer (refractive index: 1.35), a tetrafluoroethylene-hexafluoropropylene copolymer (refractive index: 1.34), poly(trifluoroethyl methacrylate) (refractive index: 1.42), polytetrafluoroethylene (refractive index: 1.35 to 1.38), hexafluoroisopropyl (meth)acrylate (refractive index: 1.31 to 1.33), and the like.

[0178] ---High refractive index resin--- The refractive index of the high refractive index resin is not particularly limited, and may be appropriately selected according to the intended purpose. The refractive index of the high refractive index resin is 1.5 or greater. The high refractive index resin is not particularly limited, as long as the high refractive index resin has a refractive index of 1.5 or greater, and may be appropriately selected according to the intended purpose. Examples of the high refractive index resin include aromatic ring-containing resins, resins including a halogen element other than fluorine, resins including an atom, such as sulfur (S), nitrogen (N), or phosphorus (P), and the like. The above resins may be used alone or in combination.

[0179] The aromatic ring-containing resins are not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the aromatic ring-containing resins include: styrol resins, such as polystyrene; polycarbonate, such as polyethylene terephthalate, polyvinylcarbazole, and bisphenol A; compounds including a fluorene skeleton; and the like.

[0180] The resins including a halogen element other than fluorine are not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the resins including a halogen element other than fluorine include polyvinyl chloride, polytetrabromobisphenol A glycidyl ether, and the like. Examples of the “halogen element other than fluorine” include bromine (Br), iodine (I), chlorine (Cl), and the like.

[0181] Examples of the resins including an atom, such as sulfur (S), nitrogen (N), and phosphorus (P), include polybisphenol S glycidyl ether, polyvinyl pyridine, and the like.

[0182] --Curable resin-- The curable resin is preferably a resin component including a monomer or oligomer having a reactive group that forms a crosslink by application of heat or ionizing radiation, more preferably a resin component including a polyfunctional monomer or polyfunctional oligomer having two or more functional groups, and yet more preferably a resin component including a polyfunctional monomer or polyfunctional oligomer having three or more functional groups.

[0183] The above resin components may be used alone or in combination.

[0184] The functional group of the polyfunctional monomer or polyfunctional oligomer cured by ionizing radiation is preferably a photopolymerizable functional group, an electron beam-polymerizable functional group, or a radiation polymerizable functional group, and more preferably a photopolymerizable functional group.

[0185] The photopolymerizable functional group is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the photopolymerizable functional group include (meth)acryloyl groups, alkenyl groups, cinnamoyl groups, cinnamylideneacetyl groups, benzalacetophenone groups, styrylpyridine groups, α-phenylmaleimide groups, phenylazide groups, sulfonylazide groups, carbonylazide groups, diazo groups, o-quinone diazide groups, furylacryloyl groups, coumarin groups, pyrone groups, anthracene groups, benzophenone groups, stilbene groups, dithiocarbamate groups, xanthate groups, 1,2,3-thiadiazole groups, cyclopropenyl groups, azadioxabicyclo groups, and the like. The above photopolymerizable functional groups may be used alone or in combination.

[0186] The photopolymerizable polyfunctional monomer is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the photopolymerizable polyfunctional monomer include: (meth)acrylic acid diesters of alkylene glycol, such as neopentylglycol acrylate, 1,6-hexanediol (meth)acrylate, and propylene glycol di(meth)acrylate; (meth)acrylic acid diester of polyoxyalkylene glycol, such as triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, pentaerythritol triacrylate, and polypropylene glycol di(meth)acrylate; (meth)acrylic acid diester of multivalent alcohol, such as pentaerythritol di(meth)acrylate and pentaerythritol tri(meth)acrylate; di(meth)acrylic acid diesters of an ethylene oxide or propylene oxide adduct, such as 2,2-bis{4-(acryloxy diethoxy)phenyl}propane, and 2,2-bis{4-(acryloxy polypropoxy)phenyl}propane; epoxy (meth)acrylates; urethane (meth)acrylates; polyester (meth)acrylates; and the like.

[0187] The curable resins are classified into low refractive index monomers and high refractive index monomers according to a refractive index.

[0188] ---Low refractive index monomer--- The refractive index of the low refractive index monomer is less than 1.5. The low refractive index monomer is not particularly limited, as long as the low refractive index monomer has a refractive index of less than 1.5, and may be appropriately selected according to the intended purpose. Examples of the low refractive index monomer include polyfunctional monomers. Specific examples of the polyfunctional monomers include 1,4-butanediol (meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentylglycol (meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, 3-methylpentadiol di(meth)acrylate, diethylene glycol bis(β-(meth)acryloyloxy)propionate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(2-hydroxyethyl)isocyanate di(meth)acrylate, pentaerythritol tetra(meth)acrylate, 2,3-bis(meth)acryloyloxyethyloxymethyl[2.2.1]heptane, poly(1,2-butadiene) di(meth)acrylate, 1,2-bis(meth)acryloyloxymethylhexane, nonaethylene glycol di(meth)acrylate, tetradecane ethylene glycol di(meth)acrylate, 10-decanediol (meth)acrylate, 3,8-bis(meth)acryloyloxymethyltricyclo[5.2.10]decane, hydrogenated bisphenol A di(meth)acrylate, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, 1,4-bis((meth)acryloyloxymethyl)cyclohexane, neopentyl glycol hydroxypivalate di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, epoxy-modified bisphenol A di(meth)acrylate, and the like.

[0189] In view of reduction in the refractive index, the low refractive index monomer may include a polyfunctional fluoromonomer. The polyfunctional fluoromonomer is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the polyfunctional fluoromonomer include 2,2,2-trifluoroethylacrylate (refractive index: 1.34), 2,2,2-trifluoroethyl(meth)acrylate, 2,2,3,3,3-pentafluoropropyl(meth)acrylate, 2-(perfluorobutyl)ethyl(meth)acrylate, 2-(perfluorohexyl)ethyl(meth)acrylate, 2-(perfluorooctyl)ethyl(meth)acrylate, 2-(perfluorodecyl)ethyl(meth)acrylate, methyl α-trifluoromethacrylate, ethyl α-trifluoromethacrylate, and the like.

[0190] ---High refractive index monomer--- The refractive index of the high refractive index monomer is 1.5 or greater. The high refractive index monomer is not particularly limited, as long as the high refractive index monomer has a refractive index of 1.5 or greater, and may be appropriately selected according to the intended purpose. Examples of the high refractive index monomer include aromatic ring-containing monomers, monomers including a halogen element other than fluorine, monomers including an atom, such as a sulfur (S), nitrogen (N), and phosphorus (P), and the like. Specific examples of the high refractive index monomer include styrene, vinyl toluene, vinyl naphthalene, vinyl biphenyl, benzyl methacrylate, bis(4-methacryloylthiophenyl)sulfide, vinylphenyl sulfide, 4-methacryloxyphenyl-4’-methoxyphenyl thioether, and the like. The above monomers may be used alone or in combination.

[0191] A molecular weight of the resin is not particularly limited, and may be appropriately selected according to the intended purpose. In view of desired resin solubility in a solvent and desired viscosity of the liquid composition, the molecular weight of the resin is preferably 5,000 or greater and less than 500,000.

[0192] A method for measuring the molecular weight of the resin is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the molecular weight of the resin can be measured by gel permeation chromatography (HLC-8320GPC EcoSEC, produced by Tosoh Corporation), multiangle light scattering (MALS) (static light scattering (SLS) using a MALS detector), or the like.

[0193] An amount of the resin is not particularly limited, and may be appropriately selected according to the intended purpose. In view of desired resin solubility in a solvent and desired viscosity of the liquid composition, the amount of the resin is preferably 1 percent by mass or greater and 50 percent by mass or less, and more preferably 1 percent by mass or greater and 30 percent by mass or less, relative to a total amount of the liquid composition.

[0194] -Photopolymerization initiator- In the case where the curable resin is used as the resin, a photopolymerization initiator is preferably used.

[0195] The photopolymerization initiator is not particularly limited, and may be appropriately selected according to the intended purpose. The photopolymerization initiator is preferably a photo-radical polymerization initiator or a photo-cationic polymerization initiator, and more preferably a photo-radical polymerization initiator. Curing of the curable resin can be performed by irradiating the liquid composition with ionizing radiation in the presence of the photo-radical polymerization initiator in the liquid composition.

[0196] The photo-radical polymerization initiator is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the photo-radical polymerization initiator include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, onium salts, borates, active halogens, and the like. The above photo-radical polymerization initiators may be used alone or in combination.

[0197] The acetophenones are not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenylketone, 1-hydroxycyclohexylphenylketone, 2-methyl-4-methylthio-2-morpholinopropiophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, and the like.

[0198] The benzoins are not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the benzoins include benzoin benzenesulfonate, benzoin toluenesulfonate, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and the like.

[0199] The benzophenones are not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone, p-chlorobenzophenone, and the like.

[0200] The phosphine oxides are not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like.

[0201] As the photopolymerization initiator, an appropriately synthesized photopolymerization initiator may be used, or a commercially available product may be used. Examples of the commercially available product of the photopolymerization initiator under a product name include: Irgacure 651, Irgacure 184, Irgacure 819, Irgacure 907, Irgacure 1870 (CGI-403 / Irg 184 = 7 / 3 mixture initiator), Irgacure 500, Irgacure 369, Irgacure 1173, Irgacure 2959, Irgacure 4265, Irgacure 4263, Irgacure 127, OXE01, and Lucirin TPO (all produced by BASF); KAYACURE DETX-S, KAYACURE BP-100, KAYACURE BDMK, KAYACURE CTX, KAYACURE BMS, KAYACURE 2-EAQ, KAYACURE ABQ, KAYACURE CPTX, KAYACURE EPD, KAYACURE ITX, KAYACURE QTX, KAYACURE BTC, and KAYACURE MCA (all produced by Nippon Kayaku Co., Ltd.); Esacure (KIP100F, KB1, EB3, BP, X33, KTO46, KT37, KIP150, TZT) (produced by Sartomer); and the like.

[0202] An amount of the photopolymerization initiator is not particularly limited, and may be appropriately selected according to the intended purpose. In view of improvement in curing speed and a reaction rate, and reduction in a residual amount of the initiator, the amount of the photopolymerization initiator is preferably 1 percent by mass or greater and 30 percent by mass or less relative to a total amount of the monomer, the oligomer, and the polymer.

[0203] -Photosensitizer- The photosensitizer is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the photosensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, Michler’s ketone, thioxanthone, and the like. In addition, one or more auxiliary agents, such as an azide compound, a thio urea compound, a mercapto compound, and the like, may be added in combination.

[0204] As the photosensitizer, an appropriately synthesized photosensitizer may be used, or a commercially available product may be used. Examples of the commercially available product of the photosensitizer under a product name include KAYACURE (DMBI, EPA) (produced by Nippon Kayaku Co., Ltd.) and the like.

[0205] -Surfactant- The surfactant is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the surfactant include fluorosurfactants, silicone surfactants, and the like.

[0206] -Rheology modifier- The rheology modifier is not particularly limited, and may be appropriately selected according to the intended purpose.

[0207] -Antioxidant- The antioxidant is not particularly limited, and may be appropriately selected according to the intended purpose.

[0208] -Antifungal agent- The antifungal agent is not particularly limited, and may be appropriately selected according to the intended purpose.

[0209] (Physical properties of liquid composition) Viscosity of the liquid composition at 25 degrees Celsius is not particularly limited, and may be appropriately selected according to the intended purpose. The viscosity of the liquid composition at 25 degrees Celsius is preferably 3 mPa-s (millipascal seconds) or greater and 1,000 mPa-s (millipascal seconds) or less, and more preferably 5 mPa-s (millipascal seconds) or greater and 20 mPa-s (millipascal seconds) or less. When the viscosity of the liquid composition is 3 mPa-s (millipascal seconds) or greater, a problem such that a mist of the liquid composition is generated can be avoided. When the viscosity of the liquid composition at 25 degrees Celsius is 1,000 mPa-s (millipascal seconds) or less, the liquid composition can be discharged by an inkjet head, a process temperature during a film formation process and a film curing process can be reduced, and the liquid composition can be easily leveled to form a homogeneous coating film.

[0210] A method for measuring the viscosity of the liquid composition is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the viscosity can be measured at 25 degrees Celsius by a rotary viscometer (Viscometer TVE-25L, produced by Tokyo Garasu Kikai Co., Ltd.), a rheometer (MCR302, produced by Anton Paar GmbH), or the like.

[0211] A surface tension of the liquid composition is not particularly limited, and may be appropriately selected according to the intended purpose. In view of homogeneousness during film formation, discharge stability of the liquid composition by inkjet printing, and storage stability of the liquid composition, the surface tension of the liquid composition is preferably 10 mN / m or greater, and more preferably 20 mN / m or greater, and preferably 40 mN / m or less, and more preferably 30 mN / m or less. When the surface tension of the liquid composition is 10 mN / m or greater, a split of a discharged droplet can be avoided. When the surface tension of the liquid composition is 40 mN / m or less, problems such that droplets are not easily leveled, and homogeneousness of a coating film is impaired can be avoided.

[0212] A method for measuring the surface tension of the liquid composition is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the surface tension of the liquid composition can be measured by a surface tensiometer (DY-300, produced by Kyowa Interface Science Co., Ltd.).

[0213] <<Film curing process>> The film curing process is a process in which the film is cured. The film curing process is suitably performed by a film curing device.

[0214] A method for curing the film is not particularly limited and may be appropriately selected according to the intended purpose. Examples of the method include natural drying, heat drying, vacuum drying, ultraviolet ray (UV) curing, heat curing, infrared ray curing, electron beam curing, two-part curing, solid-liquid separation curing, and the like. As the film curing device, for example, a hot plate, a vacuum dryer, a UV light, or the like can be used.

[0215] In the case of UV curing, curing conditions are not particularly limited, but are preferably such that irradiance is preferably 1,500 mW / cm2or greater and 5,000 mW / cm2or less, and a cumulative light dose is preferably 1,000 mJ / cm2or greater and 5,000 mJ / cm2or less.

[0216] A set temperature in the film curing process is not particularly limited, and may be appropriately set according to the intended purpose. The set temperature is preferably equal to or higher than a glass transition temperature of the resin included in the liquid composition, and equal to or higher than a boiling point of the solvent included in the liquid composition. When the temperature is set within the above range, a problem such that physical properties of a resultant optical functional layer are changed can be avoided.

[0217] The humidity in the film curing process is not particularly limited, and may be appropriately selected according to the intended purpose. The humidity is preferably 30% or lower. When the humidity is 30% or lower, problems such that curing speed is changed and optical functions may be modified due to the film including the moisture can be avoided.

[0218] The “curing” is mainly chemical film formation where a resin or the like is fused and solidified, and the “drying” is mainly physical film formation where a solvent is evaporated to solidify into a solid. The drying and curing may simultaneously occur depending on a composition of the liquid composition. In the case where drying and curing simultaneously occur, a cured state of the liquid composition can be evaluated by an evaporation amount of the solvent in the liquid composition.

[0219] In the present specification, a state where the liquid composition is 100% cured is referred to as a “100% cured state.” In other words, the 100% cured state is a state in which a solvent of the liquid composition is completely (i.e., 100 percent by mass) evaporated, or a state in which energy sufficient to completely cure the liquid composition is applied. Therefore, for example, a “50% cure state” indicates a state in which the solvent of the liquid composition is evaporated by 50 percent by mass, or a state in which energy sufficient to 50% cure the liquid composition is applied. On the other hand, a state where the liquid composition is not cured (a state of 0% cured) is referred to as a “0% cured state.”

[0220] Duration of the film curing process is not particularly limited, and may be appropriately selected according to the intended purpose. In view of distribution of the particles at the interface between layer regions in contact with each other, the duration is preferably a period which allows a cured state of the liquid composition to be 30% or greater and 100% or less.

[0221] Accordingly, the film curing process may include curing the liquid composition to a certain degree. For convenience, the phrase “curing the liquid composition to a certain degree” may be referred to as “semi-curing.”

[0222] In the case where the liquid composition is discharged by inkjet printing, as curing of one liquid composition goes through a semi-cured state, a curing state of droplets of another liquid composition in contact with droplets of the one liquid composition to be discharged can be controlled, and the optical functional layer in which a refractive index is gradually changed can be obtained.

[0223] The “certain degree” in semi-curing is not particularly limited, and may be appropriately selected according to the intended use of the optical component. For example, the cured state (dried state) of the liquid composition can be 30% or greater and less than 100%, and preferably 30% or greater and 95% or less. In the case where it is desired to adjust a difference in refractive index between the layer regions in contact with each other in the optical functional layer to be small, the cured state of the liquid composition may be 30% or greater and 70% or less.

[0224] The cured state of the droplet can be controlled by measuring the relationship between the liquid composition for use and the energy amount by the above-described measuring method in advance. In the case where drying and curing simultaneously occur, for example, the cured state of the droplet can be controlled by measuring the relationship between the cured state of the liquid composition for use and the evaporation amount of the solvent in advance.

[0225] For example, in the film curing process performed in the order of a certain number (n) in repetition, a liquid composition for producing a layer region of the certain number (n) in the order among the layer regions is semi-cured. In the film curing process performed in the order of a sequential number (n+1) in repetition, the semi-cured film of the certain number (n) and a liquid composition for producing a layer region of the sequential number (n+1) in the order are simultaneously transformed into a 100% cured state. Thus, the cured state of the layer regions in contact with each other can be adjusted, and the refractive index of the optical functional layer in the thickness direction can be more gradually changed.

[0226] In the case where the film formation process includes formation of a print pattern, moreover, one liquid composition for producing a certain number (n) of a layer region in the order, for example, the high refractive index liquid composition 42, is semi-cured in the film curing process performed in order of a certain number (n) in repetition. In the film forming process performed in order of a sequential number (n + 1) in repetition, the high refractive index liquid composition 42 and another liquid composition having a refractive index different from the higher refractive index liquid composition 42 for producing the certain number (n) of the layer region in the order, for example, the low refractive index liquid composition 41, are simultaneously transformed into 100% cured state. Thus, the cured states of the droplets having different refractive indices and being in contact with one another can be adjusted within one layer region, and the optical functional layer in which a refractive index is more gently changed within one layer region can be obtained.

[0227] A method for confirming a cured state of each layer region is not particularly limited, and may be appropriately selected according to the intended use of the optical component. For example, the cured state can be determined by a method for calculating the cured state from a change in height by a laser displacement meter, a change in weight, a change in a refractive index, a change in hardness, a change over time by a rigid-body pendulum type physical properties testing instrument (RPT-3000W, produced by A&D Company, Limited), a method for calculating the cured state from a relationship between elasticity and viscosity of the film, or the like.

[0228] Depending on the cured state of layer regions, the interface of the layer regions may be dissolved again by applying a liquid composition including particles on the layer region that does not include particles, and particles may be moved into the layer region that does not include particles.

[0229] In the case where the film curing device is a UV curing device (UV light), a light source is not particularly limited, and may be appropriately selected according to the intended purpose. Examples of the light source include high-pressure mercury lamps (Light Hammer 6, produced by Heraeus), laser emitting diodes (LEDs) (produced by Heraeus) that emit light having a wavelength of 360 nm or longer and 400 nm or shorter, and the like. The UV irradiation may be performing in a nitrogen atmosphere. The irradiance of the light source is not particularly limited, and may be appropriately selected according to the intended purpose. For example, the irradiance can be set at 0.5 W / cm2(cumulative light dose: 500 mJ / cm2to 3,000 mJ / cm2) or the like.

[0230] In the case where the film curing device is a heat curing device, a heating temperature is not particularly limited, and may be appropriately selected according to the intended purpose. The heating temperature can be appropriately selected according to a softening point of a substrate for use. For example, the heating temperature is preferably 70 degrees Celsius or higher and 200 degrees Celsius or lower in view of activation energy of a crosslinking agent included in the liquid composition and safety during curing.

[0231] In the case where the film curing device is a heat curing device, a heating time is not particularly limited, and may be appropriately selected according to the intended purpose. In view of curing of the film and productivity, the heating time is preferably 0.5 minutes or longer and 10 minutes or shorter. In addition, a hot plate or the like can be used for heating.

[0232] (Figs. 5A to 6B) Embodiments where the film formation process includes formation of a print pattern and cured states of droplets having different refractive indices and being in contact with one another within one layer region are controlled will be specifically described with reference to Figs. 5A to 6B.

[0233] Fig. 5A is a schematic side view illustrating a process where droplets of the low refractive index liquid composition 41 are discharged from the second inkjet head and cured on the optical functional layer composed of the 100% cured state of the droplets of the high refractive index liquid composition 42 discharged from the first inkjet head. Fig. 5B is a schematic side view illustrating a process where droplets of the low refractive index liquid composition 41 are discharged from the second inkjet head and cured on the optical functional layer composed of the 50% cured state of the droplets of the high refractive index liquid composition 42 discharged from the first inkjet head.

[0234] This embodiment is assumed to be a case where two liquid compositions are used, and an optical component including a single layer of the optical functional layer is produced using a high refractive index liquid composition 42 having a relatively high refractive index after curing, and a low refractive index liquid composition 41 having a relatively low refractive index after curing. First, the high refractive index liquid composition 42 is discharged onto the substrate 1, and subjected to an optical functional layer formation process, thereby transforming the high refractive index liquid composition 42 into a 100% cured state. The cured product of the high refractive index liquid composition 42 is referred to as a cured product 42a. Subsequently, the low refractive index liquid composition 41 is discharged over the cured product 42a so that droplets of the low refractive index liquid composition 41 are disposed over the substrate 1. The cured product of the low refractive index liquid composition 41, which is obtained by curing the low refractive index liquid composition 41 in a 100% cured state, is referred to as a cured product 41a. After curing, an interface 43 is formed between the cured product 42a and the cured product 41a (see Fig. 5A).

[0235] On the other hand, the high refractive index liquid composition 42 discharged on the substrate 1 is subjected to a semi-curing process, thereby transforming the high refractive index liquid composition 42 into, for example, a 50% cured state. The semi-cured product of the high refractive index liquid composition 42 is referred to as a cured product 42b. Subsequently, the low refractive index liquid composition 41 is discharged over the semi-cured product 42b so that droplets of the low refractive index liquid composition 41 are respectively arranged in gaps of the semi-cured product 42b on the substrate 1. At this time, the interface between the semi-cured product 42b and a droplet of the low refractive index liquid composition 41 is eroded. The resultant is cured so that the semi-cured product 42b and the low refractive index liquid composition 41 are transformed into a 100% cured state. Thus, the semi-cured product 42a becomes a cured product 42a. Moreover, a cured product of the low refractive index liquid composition 41 in the 100% cured state is referred to as a cured product 41a. Thus, an interface 43 is not formed, and the refractive index is gradually changed between the cured product 41a and the cured product 42a. As a result, the refractive index of the optical functional layer is changed in the planar direction of the optical functional layer (see Fig. 5B).

[0236] In the case where the print pattern is formed so that the refractive index is changed in the direction intersecting the thickness direction of the substrate 1 as described above, the optical functional layer in which the refractive direction is more gradually changed in the planar direction can be obtained by controlling the cured states of the droplets of the two or more liquid compositions having different refractive indices, which are in contact with each other in the direction intersecting with the thickness direction of the substrate, to certain cured states, respectively.

[0237] Fig. 6A is a schematic side view illustrating a process in which droplets of the low refractive index liquid composition 41 for a second layer are discharged and cured on the optical functional layer of the first layer in a 100% cured state. Fig. 6B is a schematic side view illustrating a process in which droplets of a low refractive index liquid composition 41 for a second layer are discharged on a first layer of an optical functional layer in a 50% cured state.

[0238] This embodiment is assumed to be a case where two liquid compositions are used, and an optical component including two film layers constituting the optical functional layer is produced using a high refractive index liquid composition 42 having a relatively high refractive index after curing, and a low refractive index liquid composition 41 having a relatively low refractive index after curing. First, the high refractive index liquid composition 42 is discharged onto the substrate 1, and subjected to an optical functional layer formation process, thereby transforming the high refractive index liquid composition 42 into a 100% cured state. The cured product of the high refractive index liquid composition 42 is referred to as a cured product 42a. Subsequently, the low refractive index liquid composition 41 is discharged onto the cured product 42a so that droplets of the low refractive index liquid composition 41 are disposed on the cured product 42a. The cured product of the low refractive index liquid composition 41, which is obtained by curing the low refractive index liquid composition 41 in a 100% cured state, is referred to as a cured product 41a. After curing, an interface 43 is formed between the cured product 42a as the first layer and the cured product 41a as the second layer (see Fig. 6A).

[0239] On the other hand, the high refractive index liquid composition 42 discharged on the substrate 1 is subjected to a semi-curing process, thereby transforming the high refractive index liquid composition 42 into, for example, a 50% cured state. The semi-cured product of the high refractive index liquid composition 42 is referred to as a cured product 42b. Subsequently, the low refractive index liquid composition 41 is discharged onto the semi-cured product 42b so that droplets of the low refractive index liquid composition 41 are disposed on the semi-cured product 42b. At this time, the interface between the semi-cured product 42b and the droplets of the low refractive index liquid composition 41 is eroded. The resultant is cured so that the semi-cured product 42b and the low refractive index liquid composition 41 are transformed into a 100% cured state. Thus, the semi-cured product 42a becomes a cured product 42a. Moreover, a cured product of the low refractive index liquid composition 41 in the 100% cured state is referred to as a cured product 41a. Thus, an interface 43 is not formed, and the refractive index is gradually changed between the cured product 41a and the cured product 42a. As a result, the refractive index of the optical functional layer is changed in the stacking direction of the optical functional layer (see Fig. 6B).

[0240] In the case where the print pattern is formed so that the refractive index is changed in the thickness direction of the substrate 1 as described above, the optical functional layer in which the refractive direction is gradually changed in the thickness direction can be obtained by controlling the cured states of the droplets of each of the two or more liquid compositions having different refractive indices, which are in contact with each other in the thickness direction of the substrate 1, to certain cured states, respectively.

[0241] The optical component having the print pattern with the refractive index being changed in the thickness direction of the substrate 1 can be suitably used as an antireflective film.

[0242] <Optical functional layer formation process> The optical functional layer formation process is a process in which the film formation process and the film curing process are repeated to form an optical functional layer having a uniform thickness. The optical functional layer formation device includes the film formation device and the film curing device. The optical functional layer formation process can be suitably performed by the optical functional layer formation device.

[0243] As described above, the refractive index of the optical functional layer is changed at least in the thickness direction. More specifically, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in the thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less. Moreover, the refractive index of the optical functional layer is preferably changed also in the planar direction.

[0244] The optical functional layer formation process includes performing the film formation process two or more times in which a concentration of the particles in the liquid composition is changed so that, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less. For changing the concentration of particles in the liquid composition, liquid composition having different concentrations of the particles are used. The liquid compositions having the different concentrations of the particles are preferably a combination of the liquid compositions with which a difference in refractive index between the cured liquid compositions is greater than 0 and 0.1 or less. Thus, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm in the thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other falls in the preferable range.

[0245] The optical functional layer formation process includes, among multiple film formation processes, two or more film formation processes with the liquid compositions having different concentrations of the particles. Thus, regions having different concentrations of the particles are provided within the optical functional layer so that an optical functional layer, in which, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in the thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less, can be formed.

[0246] In the optical functional layer formation process, the concentration of the particles in the liquid composition is not necessarily changed every time the film formation process is performed. In the case where the film formation process and the film curing process are each repeated three times to form an optical functional layer, for example, at the first and second film formation processes, films are formed using the same liquid composition, and at the third film formation process, a film may be formed using a liquid composition having a different concentration of the particles to the liquid composition used in the first and second film formation processes. Although the example of the optical functional layer formation process in which each of the film forming process and the film curing process is performed three times, has been described, the concentration of the particles in the liquid composition is not necessarily changed every time the film formation process is performed, also in the case where the optical functional layer forming process performs each of the film forming process and the film curing process four or more times.

[0247] In the optical functional layer formation step, the concentration of the particles included in the liquid composition is preferably changed every time the film formation process is performed. Thus, the refractive index is gradually changed from the layer region closest to the substrate to the layer region present at the outermost surface of the optical functional layer, thereby minimizing interface reflection between the layer regions.

[0248] In the optical functional layer formation process, the concentration of the particles included in the film formation process performed the (n + 1)-th time is preferably the same or lower than the concentration of the particles included in the liquid composition used in the film formation process performed the n-th time, where n is a natural number. More preferably, the concentration of the particles included in the liquid composition used in the film formation process performed the (n + 1)-th time is lower than the concentration of the particles included in the liquid composition used in the film formation process performed the n-th time. Thus, the optical functional layer, in which the concentration of the particles decreases in the direction from the layer region closest to the substrate to the layer region present at the outermost surface of the optical functional layer can be formed. Alternatively, in the optical functional layer formation process, the concentration of the particles included in the liquid composition used in the film formation process performed the (n + 1)-th time is preferably the same or greater than the concentration of the particles included in the liquid composition used in the film formation process performed the n-th time, and is more preferably greater than the concentration of the particles included in the liquid composition used in the film formation process performed the n-th time, where n is a natural number. Thus, the optical functional layer in which the concentration of the particles increases in the direction from the layer region closest to the substrate to the layer region present at the outermost surface of the optical functional layer can be formed.

[0249] Although it may depend on physical properties of liquid compositions for use, the method for producing the optical component of the present disclosure is preferably performed in the atmosphere at room temperature (25 degrees Celsius), and humidity of 20% to 30%.

[0250] Each configuration of the optical component obtained by the method for producing the optical component of the present disclosure can be confirmed, for example, by observing a surface or cross-section of the optical component by Gemini300 that is a Schottky field emission scanning electron microscope (Schottky FE-SEM), while cooling the optical component using an ion milling system IM4000 (produced by Hitachi High-Tech Corporation).

[0251] (Use) The optical component of the present disclosure can be suitably applied for an antireflective film, a light diffusion film, a high reflection film, or the like.

[0252] The present disclosure will be concretely described through Examples and Comparative Examples hereinafter, but Examples below shall not be construed as limiting the scope of the present disclosure. In Examples and Comparative Examples below, “part(s)” denotes “part(s) by mass,” and “%” denotes “percent by mass” unless otherwise stated.

[0253] (Production of liquid composition) <Production of Low refractive index liquid composition A-1> The used materials are as follows. After stirring PMMA and PGME at 60 degrees Celsius for 2 hours, the mixture was further stirred at 25 degrees Celsius for 8 hours. Then, the resultant mixture was filtered through a 2 μm-filter, thereby producing a low refractive index liquid composition A-1. -Materials- Polymethyl methacrylate (PMMA, produced by Sigma-Aldrich): 2.0 g Polypropylene glycol monomethyl ether (PGME, produced by KANTO CHEMICAL CO., LTD.): 98.0 g

[0254] <Production of low refractive index liquid composition A-2> A low refractive index liquid composition A-2 was produced in the same manner as the low refractive index liquid composition A-1, except that the materials were changed as follows. -Materials- Polynorbornene, (PNB, produced by Sumitomo Bakelite Co., Ltd.): 2.0 g Propylene glycol monomethyl ether (PGME, produced by KANTO CHEMICAL CO., LTD.): 98.0 g

[0255] <Production of low refractive index liquid composition A-3> The used materials are as follows. After stirring HFMA, PS, and PGME at 40 degrees Celsius for 2 hours, the mixture was further stirred at 25 degrees Celsius for 8 hours. Then, the resultant mixture was filtered through a 2 μm-filter, thereby producing a low refractive index liquid composition A-3. -Materials- 1,1,1,3,3,3-Hexafluoroisopropyl methacrylate (HFMA, produced by Sigma-Aldrich): 2.0 g Propylene glycol monomethyl ether (PGME, produced by KANTO CHEMICAL CO., LTD.): 98.0 g

[0256] <Production of low refractive index liquid composition A-4> The used materials are as follows. After stirring the urethane acrylate and PGME at room temperature for 1 hour, the hollow silica particles were added to the mixture, and the resultant mixture was stirred at 25 degrees Celsius for 8 hours. Then, the resultant mixture was filtered through a 2 μm-filter, thereby producing a low refractive index liquid composition A-4. -Materials- Hollow silica particles (dispersion liquid having a solid content of 20 percent by mass, average primary particle diameter: 70 nm): 1.6 g Urethane acrylate (produced by Mitsubishi Chemical Corporation): 4.6 g Propylene glycol monomethyl ether (PGME, produced by KANTO CHEMICAL CO., LTD.): 308.7 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0257] <Production of low refractive index liquid composition A-5> A low refractive index liquid composition A-5 was produced in the same manner as the low refractive index liquid composition A-4, except that the formulated amounts were changed as follows. -Materials- Hollow silica particles (dispersion liquid having a solid content of 20 percent by mass, average primary particle diameter: 70 nm): 4.7 g Urethane acrylate (produced by Mitsubishi Chemical Corporation): 4.0 g Propylene glycol monomethyl ether (PGME, produced by KANTO CHEMICAL CO., LTD.): 431.2 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0258] <Production of low refractive index liquid composition A-6> A low refractive index liquid composition A-6 was produced in the same manner as the low refractive index liquid composition A-4, except that the materials were changed as follows. -Materials- Hollow silica particles (dispersion liquid having a solid content of 20 percent by mass, average primary particle diameter: 70 nm): 12.5 g Urethane acrylate (produced by Mitsubishi Chemical Corporation): 2.4 g Propylene glycol monomethyl ether (PGME, produced by KANTO CHEMICAL CO., LTD.): 735.0 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0259] <Production of low refractive index liquid composition A-7> The used materials are as follows. After stirring the urethane acrylate and PGMEA at room temperature for 1 hour, the hollow silica particles were added to the mixture, and the resultant mixture was stirred at 25 degrees Celsius for 8 hours. Then, the resultant mixture was filtered through a 2 μm-filter, thereby producing a low refractive index liquid composition A-7. -Materials- Hollow silica particles (dispersion liquid having a solid content of 20 percent by mass, average primary particle diameter: 80 nm): 1.6 g Urethane acrylate (produced by Mitsubishi Chemical Corporation): 4.6 g Propylene glycol monomethyl ether acetate (PGMEA, produced by KANTO CHEMICAL CO., LTD.): 308.7 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0260] <Production of low refractive index liquid composition A-8> A low refractive index liquid composition A-8 was produced in the same manner as the low refractive index liquid composition A-7, except that the materials were changed as follows. -Materials- Hollow silica particles (dispersion liquid having a solid content of 20 percent by mass, average primary particle diameter: 80 nm): 12.5 g Urethane acrylate (produced by Mitsubishi Chemical Corporation): 2.4 g Propylene glycol monomethyl ether acetate (PGMEA, produced by KANTO CHEMICAL CO., LTD.): 735.0 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0261] <Production of low refractive index liquid composition A-9> The used materials are as follows. After stirring the fluorine-containing acrylate monomer and PGMEA at room temperature for 1 hour, the hollow silica particles were added to the mixture, and the resultant mixture was stirred at 25 degrees Celsius for 8 hours. Then, the resultant mixture was filtered through a 2 μm-filter, thereby producing a low refractive index liquid composition A-9. -Materials- Hollow silica particles (dispersion liquid having a solid content of 20 percent by mass, average primary particle diameter: 80 nm): 12.5 g Fluorine-containing acrylate monomer (2,2,2-trifluoroethylacrylate, produced by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.): 2.4 g Propylene glycol monomethyl ether acetate (PGMEA, produced by KANTO CHEMICAL CO., LTD.): 735.0 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0262] <Production of high refractive index liquid composition B-1> The used materials are as follows. PS and the anisole were stirred at 25 degrees Celsius for 8 hours. Then, the resultant mixture was filtered through a 2 μm-filter, thereby producing a high refractive index liquid composition B-1. -Materials- Polystyrene (PS, produced by Tosoh Corporation): 2.0 g Anisole (produced by KANTO CHEMICAL CO., LTD.): 98.0 g

[0263] <Production of high refractive index liquid composition B-2> The used materials are as follows. The zirconia nanoparticles and MEK were mixed, and the resultant mixture was stirred at 25 degrees Celsius for 2 hours. PETA and Irgacure 184 were added to the mixture, thereby producing a high refractive index liquid composition B-2. Then, the resultant mixture was filtered through a 2 μm-filter. -Materials- Zirconia nanoparticles (average primary particle diameter: 11 nm, produced by NIPPON SHOKUBAI CO., LTD.): 4.0 g Methyl ethyl ketone (MEK, produced by KANTO CHEMICAL CO., LTD.): 553.7 g Pentaerythritol triacrylate (PETA, produced by Sigma-Aldrich): 7.2 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0264] <Production of high refractive index liquid composition B-3> A high refractive index liquid composition B-3 was produced in the same manner as the high refractive index liquid composition B-2, except that the materials were changed as follows. -Materials- Zirconia nanoparticles (average primary particle diameter: 11 nm, produced by NIPPON SHOKUBAI CO., LTD.): 4.4 g Methyl ethyl ketone (MEK, produced by KANTO CHEMICAL CO., LTD.): 558.6 g Pentaerythritol triacrylate (PETA, produced by Sigma-Aldrich): 6.9 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0265] <Production of high refractive index liquid composition B-4> A high refractive index liquid composition B-4 was produced in the same manner as the high refractive index liquid composition B-2, except that the materials were changed as follows. -Materials- Zirconia nanoparticles (average primary particle diameter: 11 nm, produced by NIPPON SHOKUBAI CO., LTD.): 9.4 g Methyl ethyl ketone (MEK, produced by KANTO CHEMICAL CO., LTD.): 632.1 g Pentaerythritol triacrylate (PETA, produced by Sigma-Aldrich): 3.4 g Photopolymerization initiator: Irgacure 184: 0.1 g

[0266] The compositions of the above liquid compositions are summarized in Tables 1 and 2. Moreover, the refractive index of each liquid composition measured in the following manner is also presented in Tables 1 and 2.

[0267] (Measurement of refractive index of liquid composition) A 4 cm × 4 cm glass plate (alkali-free EAGLE XG, produced by Hiraoka Special Glass Mfg, Inc.) was prepared, and washed with acetone by an ultrasonic cleaning device. Then, the resultant glass plate was subjected to UV irradiation with low-pressure mercury lamps (UV wavelengths: 254 nm, and 185 nm) at irradiance of 3.7 mW / cm2for 10 minutes from a distance of 30 mm using a UV-ozone cleaner (UV253E, produced by Fligen, Inc.). Thereafter, a 1.0 wt% aqueous solution of a silane coupling agent (KBM-5103, produced by Shin-Etsu Chemical Co., Ltd.) was applied to the glass substrate, and was subjected to rinsing with pure water, followed by heating for 10 minutes at 100 degrees Celsius, thereby preparing the glass substrate. Each of the liquid compositions was applied onto the glass substrate by spin coating so that a film thickness became 100 nm, thereby producing a film. In order to minimize the back surface reflection of the glass substrate, scotch tape was adhered onto a side of the glass substrate on which the film was not formed. A refractive index of the produced film was measured by a spectroscopic ellipsometer M-2000 (produced by J.A. Woollam Japan). Note that the measuring conditions were as follows. -Measuring conditions- Light source: D2 lamp and QTH lamp Wavelength range: 190 nm to 1,680 nm Cumulative time: 10 s Angle of incidence: 50 degrees, 60 degrees, 70 degrees, 80 degrees

[0268]

[0269]

[0270] (Preparation of substrate) A 4 cm × 4 cm glass plate (alkali-free EAGLE XG, produced by Hiraoka Special Glass Mfg, Inc.) was prepared, and washed with acetone by an ultrasonic cleaning device. Then, the resultant glass plate was subjected to UV irradiation with low-pressure mercury lamps (UV wavelengths: 254 nm, and 185 nm) at irradiance of 3.7 mW / cm2for 10 minutes from a distance of 30 mm using a UV-ozone cleaner (UV253E, produced by Fligen, Inc.). Thereafter, a 1.0 wt% aqueous solution of a silane coupling agent (KBM-5103, produced by Shin-Etsu Chemical Co., Ltd.) was applied to the glass substrate, and was subjected to rinsing with pure water, followed by heating for 10 minutes at 100 degrees Celsius, thereby preparing the glass substrate.

[0271] (Production of optical component) Corresponding liquid compositions were applied onto the glass substrate in the predetermined order by spin coating or inkjet printing, and the applied liquid compositions were cured, thereby producing an optical functional layer. In the case where the resin included in the liquid composition was a non-curing resin, after the application of the liquid composition, the applied liquid composition was cured by heat drying at a temperature of 40 degrees Celsius for 1 hour, thereby producing an optical functional layer. In the case where the resin included in the liquid composition was a curable resin, after the application of the liquid composition, the liquid composition was cured by UV curing, thereby producing an optical functional layer. In the manner as described above, an optical component including the optical functional layer on the glass substrate was produced. Coating conditions of each liquid composition by spin coating and inkjet printing were set as follows.

[0272] -Spin coating- The liquid composition was dripped onto the glass substrate, and coated at a rotational speed of 3,000 rpm for a rotation time of 30 seconds using a spin coater (1H-DX, produced by MIKASA CO., LTD.).

[0273] -Inkjet printing- The liquid composition was applied onto the glass substrate by a printer (produced by Genesis Co., Ltd.) equipped with an inkjet head (“MH5420” produced by Ricoh Company Limited).

[0274] An ink tank and an inkjet head were prepared for each liquid composition to be coated, and were connected to each other with a tube. Thereafter, each ink tank was filled with a corresponding liquid composition. For example, in the case three liquid compositions were to be applied, the three liquid compositions were inserted into an ink tank 1, an ink tank 2, and an ink tank 3, respectively. Similarly, the liquid compositions were supplied to corresponding heads (a head 1, a head 2, and a head 3), respectively. For example, in the case where five liquid compositions were to be applied, the five liquid compositions were inserted into an ink tank 1, an ink tank 2, an ink tank 3, an ink tank 4, and an ink tank 5, respectively. Similarly, the liquid compositions were supplied to corresponding heads (a head 1, a head 2, a head 3, a head 4, and a head 5), respectively.

[0275] In the case where three liquid compositions were to be applied, the head 1, the head 2, and the head 3 were arranged to align with the scanning direction of the heads. The head 2 was set to follow the scanning of the head 1 along the same path. Similarly, the head 3 was set to follow the scanning of the head 2 along the same path. The above scanning of the heads 1 to 3 was defined as one scan.

[0276] In the case where five liquid compositions were to be applied, the head 1, the head 2, the head 3, the head 4, and the head 5 were arranged to align with the scanning direction of the heads. The head 2 was set to follow the scanning of the head 1 along the same path. Similarly, the head 3 was set to follow the scanning of the head 2 along the same path. Similarly, the head 4 was set to follow the scanning of the head 3 along the same path. Similarly, the head 5 was set to follow the scanning of the head 4 along the same path. The above scanning of the heads 1 to 5 was defined as one scan.

[0277] As the drawing conditions, a droplet amount was set to 10 pL by adjusting the applied voltage, resolution was set to 600 dpi × 600 dpi, and table transport speed was set to 45 mm / s. Moreover, the stage temperature of the printer was set at 40 degrees Celsius. The discharge data for the inkjet printing is depicted in Fig. 7. One pixel of the discharge data corresponds to one droplet discharged from one nozzle of the head. Moreover, the discharge data includes the numerical data (numerical value of 1 or more) of the two dimensional data in one pixel. In Fig. 7, one pixel is represented by a square, and the number inside the square indicates the numerical data of the two-dimensional data. The numerical data can be set as appropriate. In this example, “0” defines no discharging, and “1” defines discharging. The amount of the droplet was adjusted by applied voltage or pressure. Droplets were applied to all the pixels at once by a single pass method.

[0278] (Examples 1 to 12 and Comparative Examples 1 to 9) An optical component was produced by combining the liquid compositions as presented in Tables 3 to 7 according to [Production of optical component]. In Tables 3 to 7, “1stdischarge” denotes discharge from the head 1, “2nddischarge” denotes discharge from the head 2, “3rddischarge” denotes discharge from the head 3, “4thdischarge” denotes discharge from the head 4, and “5thdischarge” denotes discharge from the head 5. Moreover, the first discharge was set so that the thickness of the cured film of the optical functional layer was to be 100 nm. For example, if Example 1 was taken as an example, at 1stdischarge, the liquid composition A-4 was discharged so that the thickness of the coating film of the optical functional layer from 1stdischarge was to be 100 nm after being cured; at 2nddischarge, the liquid composition A-7 was discharged so that the thickness of the coating film of the optical functional layer from 2nddischarge was to be 100 nm after being cured; and at 3rddischarge, the liquid composition A-4 was discharged so that the thickness of the coating film of the optical functional layer from 3rddischarge was to be 100 nm after being cured.

[0279] (Comparative Example 10) A commercially available Mosmite film (product name: Mosmite, moth-eye-type antireflective film, produced by Mitsubishi Chemical Corporation, BA080M2C, SRF-type PET base) was acquired. The Mosmite film was adhered to the glass substrate, thereby producing an optical component of Comparative Example 10. Note that there was no difference in the refractive index in the thickness direction of the moth-eye film, which was measured based on below (Measurement of refractive index of optical component).

[0280] The optical components of Examples 1 to 24 and Comparative Examples 1 and 2 were measured or evaluated as follows.

[0281] (Measurement of refractive index of optical functional layer) In order to minimize the back surface reflection of the glass substrate, scotch tape was adhered to the glass substrate. A difference in refractive index between the layer regions was measured by a spectroscopic ellipsometer M-2000 (produced by J.A. Woollam Japan), and the measured results were evaluated based on the following evaluation criteria. Note that measuring conditions were as follows. The results are presented in Tables 3 to 7. Note that the layer regions were determined by evenly dividing the optical functional layer from the interface between the glass substrate and the optical functional layer in the thickness direction of the optical functional layer by 100 nm. -Measuring conditions- Light source: D2 lamp and QTH lamp Wavelength range: 190 nm to 1,680 nm Cumulative time: 10 s Angle of incidence: 50 degrees, 60 degrees, 70 degrees, and 80 degrees -Evaluation criteria - A: the difference in the refractive index between the layer regions was greater than 0 and 0.1 or less B: the difference in refractive index between the layer regions was 0, or greater than 0.1

[0282] (Measurement of thickness of optical functional layer) A groove was formed in the surface of the optical functional layer by a cutter, and the film thickness was measured by a stylus surface profiler (Alpha-Step D-500, produced by ULVAC, Inc.). The results are presented in Tables 3 to 7.

[0283] (Evaluation of average reflectance of optical component) In order to minimize the back surface reflection of the glass substrate, the glass substrate was painted in black by a black spray (Aspen lacquer spray matte black), and a black paper sheet was further placed on the back surface side of the glass substrate. The reflectance of the optical component was evaluated using a spectrophotometer (V-770, produced by JASCO Corporation) by setting the angle of incidence to the range of 5 degrees. The measuring conditions are as follows. The average reflectance [%] in the visible spectral region was calculated from the obtained reflection spectrum. The results are presented in Tables 3 to 7. -Measuring conditions- Measuring range: 780 nm to 380 nm (visible spectrum) Data input interval: 0.5 nm UV / Vis bandwidth: 5.0 nm NIR bandwidth: 20.0 nm UV / Vis response: 0.24 sec NIR response: 0.24 sec Scanning mode: continuous Scanning speed: 200 nm / min Light source switch: 340 nm Diffraction grating switch: 850 nm Light source: D2 / WI Filter switch: step Correction: baseline / dark

[0284] (Evaluation of wavelength dependency of optical component) In the same manner as in the evaluation of the average reflectance, the maximum reflectance and the minimum reflectance of the optical component with respect to visible light were measured. The wavelength dependency was calculated from an absolute value ΔR of the difference between the maximum reflectance and the minimum reflectance. The wavelength dependency of 5% or lower was determined as being acceptable. The results are presented in Tables 3 to 7.

[0285] (Evaluation of average transmittance of optical component) The average transmittance of the optical component was measured by setting the angle of incidence at 0 degrees and using a spectrophotometer (V-770, produced by JASCO Corporation), and was evaluated. The measuring conditions are as follows. The results are presented in Tables 3 to 7. -Measuring conditions- Measuring range: 780 nm to 380 nm Data input interval: 0.5 nm UV / Vis bandwidth: 5.0 nm NIR bandwidth: 20.0 nm UV / Vis response: 0.24 sec NIR response: 0.24 sec Scanning mode: continuous Scanning speed: 200 nm / min Light source switch: 340 nm Diffraction grating switch: 850 nm Light source: D2 / WI Filter switch: step Correction: baseline / dark

[0286] (Evaluation of haze value of optical component) The haze value of the optical component including the glass substrate serving as the substrate was measured by a haze meter (NDH 5000, produced by DENSHOKU INDUSTRIES Co., Ltd.) according to JIS-K-7136:2000 (ISO 14782 : 1999). Note that the haze value of only the glass substrate used was 0.23%. The results are presented in Tables 3 to 7.

[0287] (Evaluation of film strength of optical functional layer) As an evaluation of the film strength of the optical functional layer, an abrasion resistance test and an adhesion test were performed.

[0288] <Abrasion resistance test> The optical component was placed on a smooth table in a manner such that the side of the optical component where the optical functional layer was disposed faced upward, and the surface of the optical functional layer of the optical component was rubbed 10 times in reciprocating actions with #0000 steel wool with a load of 200 g per 2.5 cm2, and scratches formed in the rubbing direction and in the direction perpendicular to the rubbing direction within the range of 2 cm were visually observed. The results were evaluated based on the following evaluation criteria. The results are presented in Tables 3 to 7. -Evaluation criteria- A: There was no scratch at all and no problem as a product. B: There was a slight scratch, but no problem as a product. C: There were many scratches and was a problem as a product.

[0289] <Adhesion test> Eleven lines of cuts each having a width of 1 mm were formed along the width and the length respectively on the optical functional layer using a cutter, thereby forming 100 squares of 1 mm2(cross-cut), and tape (cellophane tape No. 29, produced by Nitto Denko Corporation) was adhered thereon. Subsequently, after rubbing the optical component with a spatula 10 times in reciprocating actions, the tape was vigorously removed. This operation was performed three times, and a degree of peeling of the film was visually observed. The results were evaluated based on the following evaluation criteria. The results are presented in Tables 3 to 7. -Evaluation criteria- A: There was no peeling and no problem as a product. B: There was slight peeling, but was no problem as a product. C: There were many peeled portions, and was a problem as a product.

[0290]

[0291]

[0292]

[0293]

[0294]

[0295] The optical functional layer of the optical component according to the present embodiment preferably includes a region in which a refractive index varies in a planar direction of the optical functional layer. With the above optical component, high productivity is achieved, and a refractive index can be highly precisely controlled.

[0296] A method for producing an optical component preferably includes discharging two or more liquid compositions having different refractive indices onto a substrate to form a print pattern in a direction intersecting a thickness direction of the substrate (print pattern formation step), and curing the print pattern to form an optical functional layer (optical functional layer formation step). In the print pattern formation step, one liquid composition and another liquid composition having a different refractive index from the refractive index of one liquid composition are discharged to be in contact with each other in the direction intersecting the thickness direction of the substrate, thereby producing the optical component.

[0297] The optical component of the above embodiment will be concretely described through Examples hereinafter. (Example 13)

[0298] The above-described low refractive index liquid composition A-1 was used as a high refractive index liquid composition, and the above described low index liquid composition A-2 was used as a low refractive index liquid composition.

[0299] (Preparation of substrate) A 4 cm × 4 cm glass plate (Eagle XG, produced by TECHNO PRINT CO., LTD.) was prepared, and washed with acetone by an ultrasonic cleaning device. Then, the resultant glass plate was subjected to UV irradiation with low-pressure mercury lamps (UV wavelengths: 254 nm, and 185 nm) at irradiance of 2 mW / cm2for 10 minutes from a distance of 30 mm using a UV-ozone cleaner, thereby preparing the glass substrate.

[0300] (Inkjet printing) The liquid composition was applied onto the glass substrate by a printer (produced by Genesis Co., Ltd.) equipped with an inkjet head (“MH5420” produced by Ricoh Company Limited).

[0301] (Drawing conditions) As the drawing conditions, a droplet amount was set to 3 pL by adjusting the applied voltage, resolution was set to 600 dpi × 600 dpi, and table transport speed was set to 45 mm / s. Moreover, the stage temperature of the printer was set at 60 degrees Celsius.

[0302] An optical component illustrated in Fig. 4A was produced using the above materials and under the above-described conditions. Specifically, the layer regions 22, 23, and 24 of the optical functional layer of Fig. 4A were formed in this order, thereby forming the optical functional layer. The dark region (with a higher concentration of dots) of the optical functional layer in Fig. 4A was formed in a manner such that a ratio of the high refractive index liquid composition to the total amount of the discharged liquid compositions was higher than the ratio in the pale region (with a lower concentration of dots) of the optical functional layer.

[0303] (Example 14) An optical component was produced under the same conditions as in Example 13, except that the optical component illustrated in Fig. 8 was produced. The darker the color of the layer regions 31, 32, and 33 of the optical functional layer illustrated in fig. 8 is, higher the refractive index is. Specifically, the layer regions 31, 32, and 33 of the optical functional layer of Fig. 8 were formed in this order, thereby forming the optical functional layer. The dark region (with a higher concentration of dots) of the optical functional layer in Fig. 8 was formed in a manner such that a ratio of the high refractive index liquid composition to the total amount of the discharged liquid compositions was higher than the ratio in the pale region (with a lower concentration of dots) of the optical functional layer.

[0304] (Measurement of refractive index of optical functional layer) In order to minimize the back surface reflection of the glass substrate, scotch tape was adhered to the glass substrate. A refractive index of the optical component was measured by a spectroscopic ellipsometer M-2000 (produced by J.A. Woollam Japan). Measuring conditions were as follows. As a light source, a D2 lamp and a QTH lamp were used. A wavelength range was 190 nm to 1,680 nm. A cumulative time was 10 s. Angles of incidence was 50 degrees, 60 degrees, 70 degrees, and 80 degrees. A refractive index distribution was calculated from a film thickness and a refractive index. The refractive index was measured on randomly selected 3 points on each of the optical components of Examples 13 and 14. The measured refractive index values for both optical components had a deviation of 0.05 or less from a target value of the refractive index, and therefore it was found that the optical components of Examples 13 and 14 can be used as antireflective films.

[0305] The optical functional layer composed of three films obtained in each of Examples 13 and 14 had a difference in the concentration of the high refractive index liquid composition or the low refractive index liquid composition in the direction intersecting the thickness direction of the substrate, and therefore there was the refractive index distribution in the direction intersecting the thickness direction of the substrate.

[0306] For example, embodiments of the present disclosure are as follows. <1> An optical component including: a substrate; and an optical functional layer disposed over the substrate, the optical functional layer including particles and having a uniform thickness, wherein, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less. <2> The optical component according to <1>, wherein each of the layer regions of the optical functional layer has a refractive index of 1.0 or greater and 2.5 or less. <3> The optical component according to <1> or <2>, wherein a refractive index of the optical functional layer increases in a direction from the layer region closest to the substrate to the layer region present at an outermost surface of the optical functional layer. <4> The optical component according to <1> or <2>, wherein a refractive index of the optical functional layer decreases in a direction from the layer region closest to the substrate to the layer region present at an outermost surface of the optical functional layer. <5> The optical component according to any one of <1> to <4>, wherein the optical functional layer includes one group of the particles, and the pair of the layer regions in contact with each other in the optical functional layer have different concentrations of the particles. <6> The optical component according to any one of <1> to <4>, wherein the optical functional layer includes two or more groups of the particles having different refractive indices, and the pair of the layer regions in contact with each other in the optical functional layer have different concentrations of the two or more groups of the particles having different refractive indices. <7> The optical component according to any one of <1> to <6>, wherein the particles include at least one selected from the group consisting of polymer particles, silica particles, and oxide particles. <8> The optical component according to any one of <1> to <7>, wherein a difference between a maximum reflectance of the optical component in a visible spectral region measured at an angle of incidence of 5 degrees and a minimum reflectance of the optical component in a visible spectral region measured at an angle of incidence of 5 degrees is 5% or less. <9> The optical component according to any one of <1> to <8>, wherein all of the layer regions of the optical functional layer include the particles. <10> The optical component according to any one of <1> to <9>, wherein the optical functional layer includes regions having different refractive indices, the regions having different refractive indices being arranged in a planar direction of the optical functional layer. <11> A method for producing an optical component, the method including: discharging a liquid composition including particles onto a substrate to form a film; curing the film; and repeating the discharging and the curing to form an optical functional layer having a uniform thickness, wherein the repeating includes performing the discharging two or more times in which a concentration of the particles in the liquid composition is changed so that, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less. <12> The method according to <11>, wherein the discharging includes discharging two or more liquid compositions having different refractive indices onto the substrate by inkjet printing to form a print pattern in a direction intersecting a thickness direction of the substrate, and the formation of the print pattern is achieved by discharging the two or more liquid compositions such that among the two or more liquid compositions, one liquid composition and another liquid composition having a different refractive index from the one liquid composition are in contact with each other in the direction intersecting the thickness direction of the substrate. <13> The method according to <12>, wherein the formation of the print pattern is achieved by discharging the two or more liquid compositions having different refractive indices in a manner such that a refractive index of the optical functional layer is changed at least in one direction intersecting the thickness direction of the substrate. <14> The method according to any one of <11> to <13>, wherein the discharging includes discharging the two or more liquid compositions having different refractive indices while changing discharge amounts of the two or more liquid compositions. <15> The method according to any one of <11> to <14>, wherein the curing includes curing the liquid composition to a certain degree.

[0307] The optical component according to any one of <1> to <10>, and the method for producing the optical component according to any one of <11> to <15> can solve the various problems existing in the related art, and can achieve the object of the present invention.

[0308] This application is based upon and claims priority to Japanese Patent Application No. 2024-100832, filed on June 21, 2024, Japanese Patent Application No. 2024-100835, filed on June 21, 2024, Japanese Patent Application No. 2025-082063, filed on May 15, 2025, and Japanese Patent Application No. 2025-082071, filed on May 15, 2025, the entirety of which is incorporated herein by reference.

[0309] 1 substrate 20 optical functional layer 21 first layer region 22 second layer region 23 third layer region 24 fourth layer region 25 fifth layer region 26 sixth layer region 27 seventh layer region 31 particles 32 resin 41 low refractive index liquid composition 42 high refractive index liquid composition 101 optical component 102 optical component 103 optical component X1 center X2 center

Claims

1. An optical component comprising: a substrate; and an optical functional layer disposed over the substrate, the optical functional layer including particles and having a uniform thickness, wherein, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less.

2. The optical component according to claim 1, wherein each of the layer regions of the optical functional layer has a refractive index of 1.0 or greater and 2.5 or less.

3. The optical component according to claim 1, wherein a refractive index of the optical functional layer increases in a direction from the layer region closest to the substrate to the layer region present at an outermost surface of the optical functional layer.

4. The optical component according to claim 1, wherein a refractive index of the optical functional layer decreases in a direction from the layer region closest to the substrate to the layer region present at an outermost surface of the optical functional layer.

5. The optical component according to claim 1, wherein the optical functional layer includes one group of the particles, and the pair of the layer regions in contact with each other in the optical functional layer have different concentrations of the particles.

6. The optical component according to claim 1, wherein the optical functional layer includes two or more groups of the particles having different refractive indices, and the pair of the layer regions in contact with each other in the optical functional layer have different concentrations of the two or more groups of the particles having different refractive indices.

7. The optical component according to claim 1, wherein the particles include at least one selected from the group consisting of polymer particles, silica particles, and oxide particles.

8. The optical component according to claim 6, wherein a difference between a maximum reflectance of the optical component in a visible spectral region measured at an angle of incidence of 5 degrees and a minimum reflectance of the optical component in a visible spectral region measured at an angle of incidence of 5 degrees is 5% or less.

9. The optical component according to claim 1, wherein all of the layer regions of the optical functional layer include the particles.

10. The optical component according to claim 1, wherein the optical functional layer includes regions having different refractive indices, the regions having different refractive indices being arranged in a planar direction of the optical functional layer.

11. A method for producing an optical component, the method comprising: discharging a liquid composition including particles onto a substrate to form a film; curing the film; and repeating the discharging and the curing to form an optical functional layer having a uniform thickness, wherein the repeating includes performing the discharging two or more times in which a concentration of the particles in the liquid composition is changed so that, when the optical functional layer is divided into layer regions by dividing the optical functional layer by 100 nm from a surface of the optical functional layer closest to the substrate in a thickness direction of the optical functional layer, a difference in refractive index between at least one pair of the layer regions in contact with each other is greater than 0 and 0.1 or less.

12. The method according to claim 11, wherein the discharging includes discharging two or more liquid compositions having different refractive indices onto the substrate by inkjet printing to form a print pattern in a direction intersecting a thickness direction of the substrate, and the formation of the print pattern is achieved by discharging the two or more liquid compositions such that among the two or more liquid compositions, one liquid composition and another liquid composition having a different refractive index from the one liquid composition are in contact with each other in the direction intersecting the thickness direction of the substrate.

13. The method according to claim 12, wherein the formation of the print pattern is achieved by discharging the two or more liquid compositions having different refractive indices in a manner such that a refractive index of the optical functional layer is changed at least in one direction intersecting the thickness direction of the substrate.

14. The method according to claim 11, wherein the discharging includes discharging the two or more liquid compositions having different refractive indices while changing discharge amounts of the two or more liquid compositions.

15. The method according to claim 11, wherein the curing includes curing the liquid composition to a certain degree.

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