Method for manufacturing a dispersion, dispersion, low refractive index layer, optical component, optical device, method for manufacturing a low refractive index layer, method for manufacturing an optical component, and method for manufacturing an optical device

Abstract

Provided is a production method for a dispersion liquid capable of ensuring the film thickness of a low refractive index layer and achieving in-plane film thickness uniformity.　This production method is for a dispersion liquid in which particles are dispersed in a dispersion medium, the method being characterized in that: the particles are particles of a condensate of a material containing an alkoxy silane, that is, a condensate of a material containing a trifunctional organic silicon; a first pulverization step, a condensing step, and a second pulverization step are performed in the stated order; the first pulverization step is for pulverizing the particles in a liquid in which the particles are dispersed in the dispersion medium; the condensing step is for condensing the liquid; the second pulverization step is for further pulverizing the particles, in the liquid, pulverized in the first pulverization step; the viscosity of the liquid after the second pulverization step is greater than the viscosity of the liquid after the first pulverization step, or the concentration of the particles in the liquid after the second pulverization step is greater than the concentration of the particles in the liquid after the first pulverization step; and the density of the particles in the produced dispersion liquid is 3.5 wt% or more.

Description

[Technical Field]

[0001] This disclosure relates to a method for producing a dispersion, a dispersion, a low refractive index layer, an optical component, an optical device, a method for producing a low refractive index layer, a method for producing an optical component, and a method for producing an optical device. [Background technology]

[0002] In optical devices, for example, an air layer with a low refractive index is used as the total reflection layer. Specifically, for example, in liquid crystal devices, each optical film component (e.g., a light guide plate and a reflector plate) is laminated with an air layer in between. However, when components are separated by an air layer, problems such as component deflection may occur, especially when the components are large.

[0003] Therefore, it has been proposed to use a low refractive index layer instead of an air layer. For example, a method has been used in which a low refractive index layer is formed on a light guide plate, optically isolating the light guided into the light guide plate, and guiding the light without being affected by external factors such as dirt or scratches on the light guide plate. Patent Document 1 describes a method in which a low refractive index layer is laminated via an adhesive layer that is bonded to the light guide plate for the purpose of protecting the light.

[0004] As a method for forming such a low refractive index layer, for example, Patent Document 2 describes the application of a coating solution by roll-to-roll application. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 6606518 [Patent Document 2] Patent No. 6599699 [Overview of the project] [Problems that the invention aims to solve]

[0006] When a low refractive index layer is laminated via an adhesive layer, as described in Patent Document 1, the light guided through the light guide plate passes through the adhesive layer before total internal reflection occurs at the low refractive index layer. This can lead to color shifts and light scattering originating from the adhesive layer, potentially resulting in light guide loss. Therefore, a method has been proposed in which a coating liquid is directly applied to the light guide plate to form the low refractive index layer without using an adhesive layer.

[0007] However, since light guide plates are manufactured in batches, direct coating with liquid requires a batch coating machine, spin coating, spray coating, dipping, or other coating methods different from die coating used in normal roll coating. Among these batch coating methods, spin coating is the easiest to ensure in-plane smoothness. However, the liquid for forming the low refractive index layer described in Patent Document 2 is designed based on a roll-to-roll coating method, and is therefore insufficient for ensuring film thickness after drying in spin coating and for considering the spread of the liquid during spin coating. In particular, for AR / MR glasses, which are small device components, ensuring the film thickness of the low refractive index layer and in-plane film thickness uniformity are important in order to maintain the parallelism between light guide plates, and in the design of the liquid for spin coating, it is necessary to appropriately manage and design items such as viscosity and concentration.

[0008] Therefore, the present disclosure aims to provide a method for manufacturing a dispersion that can ensure the thickness of the low refractive index layer and achieve uniformity of the in-plane film thickness, a dispersion, a low refractive index layer, an optical component, an optical device, a method for manufacturing the low refractive index layer, a method for manufacturing the optical component, and a method for manufacturing the optical device. [Means for solving the problem]

[0009] To achieve the aforementioned objective, the method for producing the first dispersion of this disclosure is as follows: A method for producing a dispersion liquid in which particles are dispersed in a dispersion medium, The aforementioned particles are condensates of raw materials containing alkoxysilane, The first grinding step, the concentration step, and the second grinding step are carried out in this order. The first grinding step is a step of grinding the particles in the liquid in which the particles are dispersed in the dispersion medium, The aforementioned concentration step is a step of concentrating the liquid, The second grinding step is a step of further grinding the particles in the liquid that were ground in the first grinding step, The viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the particles in the liquid after the second grinding step is greater than the concentration of the particles in the liquid after the first grinding step. The manufactured dispersion is characterized in that the concentration of the particles is 3.5% by weight or more.

[0010] To achieve the aforementioned objective, the method for producing the second dispersion of this disclosure is as follows: A method for producing a dispersion liquid in which solid components containing particles are dispersed in a dispersion medium, The aforementioned particles are condensates of raw materials containing alkoxysilane, The first grinding step, the concentration step, and the second grinding step are carried out in this order. The first grinding step is a step of grinding the particles in the liquid in which the solid content is dispersed in the dispersion medium, The aforementioned concentration step is a step of concentrating the liquid, The second grinding step is a step of further grinding the particles in the liquid that were ground in the first grinding step, The viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the solids in the liquid after the second grinding step is greater than the concentration of the solids in the liquid after the first grinding step. The manufactured dispersion is characterized in that the concentration of the solid content is 3.5% by weight or more. In the following, "method for producing the dispersion of the Disclosure" includes both the first method for producing the dispersion of the Disclosure and the second method for producing the dispersion of the Disclosure, unless otherwise specified.

[0011] The dispersion of this disclosure is characterized by being manufactured by the method for manufacturing the dispersion of this disclosure.

[0012] The low refractive index layer of the present disclosure is obtained by coating and drying the dispersion of the present disclosure.

[0013] The optical member of the present disclosure includes the low refractive index layer of the present disclosure.

[0014] The optical device of the present disclosure includes the optical member of the present disclosure.

[0015] The method for manufacturing the low refractive index layer of the present disclosure includes a step of manufacturing the dispersion of the present disclosure by the method for manufacturing the dispersion of the present disclosure, a step of coating the dispersion of the present disclosure on a substrate, and a step of drying the coated dispersion.

[0016] The method for manufacturing the optical member of the present disclosure is a method for manufacturing an optical member including a low refractive index layer, and is characterized in that the low refractive index layer is manufactured by the manufacturing method of the present disclosure.

[0017] The method for manufacturing the optical device of the present disclosure is a method for manufacturing an optical device including an optical member, and is characterized in that the optical member is manufactured by the manufacturing method of the present disclosure.

Advantages of the Invention

[0018] According to the present disclosure, it is possible to provide a method for manufacturing a dispersion, a dispersion, a low refractive index layer, an optical member, an optical device, a method for manufacturing a low refractive index layer, a method for manufacturing an optical member, and an optical device, which can ensure the film thickness of the low refractive index layer and realize the in-plane film thickness uniformity.

Modes for Carrying Out the Invention

[0019] Next, the present disclosure will be described more specifically with examples. However, the present disclosure is not limited in any way by the following description.

[0020] In this disclosure, the "solvent" (e.g., a solvent for gel production used in the production of a dispersion, a substitution solvent, a solvent for producing a low refractive index layer, etc.) does not necessarily have to dissolve the gel or its pulverized material, particles, etc. For example, the gel or its pulverized material, etc. may be dispersed or precipitated in the solvent. For example, an organic solvent may be used as the dispersion medium in the dispersion of this disclosure.

[0021] In this disclosure, “adhesive layer” means a layer formed by at least one of an adhesive and an adhesive. In this disclosure, unless otherwise specified, an “adhesive layer” may be an “adhesive layer” formed by an adhesive, an “adhesive layer” formed by an adhesive, or a layer containing both an adhesive and an adhesive. In this disclosure, adhesives and adhesives may be collectively referred to as “adhesive.” Generally, agents with relatively weak adhesive strength (e.g., agents that allow for re-peeling of the bonded object) are sometimes called “adhesives,” and agents with relatively strong adhesive strength (e.g., agents that make re-peeling of the bonded object impossible or extremely difficult) are sometimes called “adhesives.” In this disclosure, there is no clear distinction between adhesives and adhesives. Also, in this disclosure, there is no clear distinction between “adhesive strength” and “bonding strength.”

[0022] In this disclosure, unless otherwise specified, "mass%" and "weight%" may be interpreted as interchangeable, and "parts of mass" and "parts of weight" may be interpreted as interchangeable.

[0023] Furthermore, in this disclosure, "on top of" or "on the surface" may refer to a state of direct contact with the top of or on the surface, or it may refer to a state of contact with other layers, etc.

[0024] [1. Dispersion and method for producing the same] The method for producing the first dispersion of this disclosure is as described above. A method for producing a dispersion liquid in which particles are dispersed in a dispersion medium, The aforementioned particles are condensates of raw materials containing alkoxysilane, The first grinding step, the concentration step, and the second grinding step are carried out in this order. The first grinding step is a step of grinding the particles in the liquid in which the particles are dispersed in the dispersion medium, The aforementioned concentration step is a step of concentrating the liquid, The second grinding step is a step of further grinding the particles in the liquid that were ground in the first grinding step, The viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the particles in the liquid after the second grinding step is greater than the concentration of the particles in the liquid after the first grinding step. The manufactured dispersion is characterized in that the concentration of the particles is 3.5% by weight or more.

[0025] The method for producing the second dispersion of this disclosure is as described above. A method for producing a dispersion liquid in which solid components containing particles are dispersed in a dispersion medium, The aforementioned particles are condensates of raw materials containing alkoxysilane, The first grinding step, the concentration step, and the second grinding step are carried out in this order. The first grinding step is a step of grinding the particles in the liquid in which the solid content is dispersed in the dispersion medium, The aforementioned concentration step is a step of concentrating the liquid, The second grinding step is a step of further grinding the particles in the liquid that were ground in the first grinding step, The viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the solids in the liquid after the second grinding step is greater than the concentration of the solids in the liquid after the first grinding step. The manufactured dispersion is characterized in that the concentration of the solid content is 3.5% by weight or more.

[0026] Furthermore, the dispersion of this disclosure is characterized by being manufactured by the method for manufacturing the dispersion of this disclosure.

[0027] [1-1. Particles of condensate products of raw materials containing alkoxysilane] In the dispersion of the present disclosure, the particles are, as described above, condensates of raw materials containing alkoxysilane. The alkoxysilane may be, for example, a saturated alkoxysilane or an unsaturated alkoxysilane having UV-polymerizable unsaturated groups. The saturated alkoxysilane may be, for example, a monomer, an oligomer, or a combination thereof. Specific examples of the saturated alkoxysilane monomer include methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, diethoxydimethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane, and these may be used individually or in combination of multiple types. The saturated alkoxysilane oligomer is preferably a condensate polymer of one or more of the above monomers. The saturated alkoxysilane oligomer can be obtained, for example, by hydrolysis polymerization of the monomer. The alkoxysilane is preferably an alkoxysilane having three or fewer functional groups (saturated bond functional groups). The unsaturated alkoxysilane may be, for example, a monomer, an oligomer, or a combination thereof. The unsaturated alkoxysilane monomer may, for example, have an organic group having at least one double or triple bond and an alkoxy group.

[0028] In the dispersion of the present disclosure, the particles may be, for example, particles of a silsesquioxane condensate which is a condensate of a raw material containing a trifunctional organosilicon compound. In this case, the particles may be, for example, a condensate of a raw material consisting only of a trifunctional organosilicon compound, or a condensate of a raw material containing a trifunctional organosilicon compound and other monomers. The content of the trifunctional organosilicon compound in the raw material (monomer) may be, for example, 0.1 moL% or more, 10 moL% or more, 30 moL% or more, 50 moL% or more, or 90 moL% or more, for example, 100 moL% or less, 99 moL% or less, 90 moL% or less, 70 moL% or less, or 50 moL% or less, for example, 0.1 to 100 moL%, 1 to 99 moL%, 10 to 90 moL%, or 30 to 70 moL%.

[0029] The raw material (monomer) of the particles may, for example, include an organosilicon compound represented by the following formula (1). In this case, the raw material may or may not include other components. Since the organosilicon compound of the following formula (1) has hydroxyl groups, hydrogen bonding or intermolecular force bonding is possible, for example, through each hydroxyl group.

[0030] [ka]

[0031] In formula (1), for example, X is 2, 3, or 4, provided that at least a portion of the raw materials represented by formula (1) is a trifunctional organosilicon compound in which X is 3, and R 1 is a linear or branched alkyl group. 1 The number of carbon atoms is, for example, 1-6, 1-4, or 1-2. Examples of the linear alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and so on, while examples of the branched alkyl group include an isopropyl group, an isobutyl group, and so on. X is, for example, 3 or 4.

[0032] Among the organosilicon compounds represented by formula (1) above, the trifunctional organosilicon compounds in which X is 3 can be represented by the following formula (1'). In the following formula (1'), R 1 This is the same as in formula (1) above, and is, for example, a methyl group. 1 When X is a methyl group, the organosilicon compound is tris(hydroxy)methylsilane. When X is 3, the organosilicon compound is, for example, a trifunctional silane having three functional groups.

[0033] [ka]

[0034] Further, specific examples of the silicon compound represented by the formula (1) include, for example, compounds where X is 4. In this case, the silicon compound is, for example, a tetrafunctional silane having four functional groups.

[0035] The silicon compound may be, for example, a precursor that forms the silicon compound of the formula (1) by hydrolysis. As the precursor, for example, any substance that can generate the silicon compound by hydrolysis may be used, and specific examples include compounds represented by the following formula (2).

Chemical formula

[0036] In the formula (2), for example, X is 2, 3, or 4, R 1 and R 2 are each a linear or branched alkyl group, R 1 and R 2 may be the same or different, R 1 when X is 2, may be the same or different from each other, R 2 may be the same or different from each other.

[0037] The X and R 1 are, for example, the same as X and R 1 in the formula (1) described later. Also, the R 2 is, for example, the same as R 1 in the formula (1) described later, and the exemplifications thereof can be cited.

[0038] Specific examples of the silicon compound represented by the formula (2) include, for example, compounds represented by the following formula (2’) where X is 3. In the following formula (2’), R 1 and R 2 are each the same as in the formula (2). R 1 and R 2When is a methyl group, the silicon compound is trimethoxy(methyl)silane (hereinafter also referred to as "MTMS"). The compound represented by formula (1') can be obtained by hydrolyzing the compound represented by the following formula (2'). [ka]

[0039] If the silicon compound is a precursor represented by formula (2), the manufacturing method of the present invention may include, for example, a step of hydrolyzing the precursor.

[0040] Particles of the condensate of the raw material containing alkoxysilane can be produced, for example, as a sol particle liquid in which the particles are dispersed in a dispersion medium. The method for producing the sol particle liquid is not particularly limited, but for example, it can be produced by grinding the gel of the condensate of the raw material containing alkoxysilane in a dispersion medium. The method for producing the gel of the condensate of the raw material containing alkoxysilane is also not particularly limited, but for example, it can be produced in a manner similar to the method for producing a silicon compound gel described in International Publication No. 2019 / 065999 or International Publication No. 2019 / 065803. The method for grinding the gel of the condensate of the raw material containing alkoxysilane in a dispersion medium is also not particularly limited, but for example, the method described in Japanese Patent No. 7182358 may be used. The type of dispersion medium in the sol particle liquid is also not particularly limited, but for example, it may be the same as the dispersion medium for the sol particle liquid described in International Publication No. 2019 / 065999 or International Publication No. 2019 / 065803. Furthermore, the sol particle liquid can also be manufactured, for example, by the method described in "Reference Example 1" of the embodiments of this application, which will be described later.

[0041] [1-2. Method for producing dispersion] The method for producing the dispersion of this disclosure is not particularly limited, but it can be produced, for example, as follows.

[0042] First, a sol particle solution is produced in which particles of a condensate of a raw material containing alkoxysilane are dispersed in a dispersion medium. The particles of the condensate of the raw material containing alkoxysilane may, for example, be particles of a silsesquioxane condensate, as described above. The sol particle solution can be produced, for example, by the method described above. The concentration of the particles of the condensate of the raw material containing alkoxysilane in the sol particle solution at this stage is not particularly limited, but may be, for example, 0.5% by weight or more, 1.0% by weight or more, 2.0% by weight or more, 2.5% by weight or more, or 3.0% by weight or more, or for example, 3.5% by weight or less, 3.4% by weight or less, 3.3% by weight or less, 3.2% by weight or less, or 3.1% by weight or less, or for example, 0.5 to 3.5% by weight, 1.0 to 3.4% by weight, 2.0 to 3.3% by weight, 2.5 to 3.2% by weight, or 3.0 to 3.1% by weight. Furthermore, the concentration of components other than the dispersion medium in the sol particle liquid at this stage (hereinafter sometimes referred to as "solid content" or "solid components") is not particularly limited, but may be, for example, 0.5% by weight or more, 1.0% by weight or more, 2.0% by weight or more, 2.5% by weight or more, or 3.0% by weight or more, or for example, 3.5% by weight or less, 3.4% by weight or less, 3.3% by weight or less, 3.2% by weight or less, or 3.1% by weight or less, or for example, 0.5 to 3.5% by weight, 1.0 to 3.4% by weight, 2.0 to 3.3% by weight, 2.5 to 3.2% by weight, or 3.0 to 3.1% by weight.

[0043] In this disclosure, particle size can be measured by, for example, a laser diffraction particle size analyzer or a dynamic light scattering particle size analyzer (DLS). However, in this disclosure, it is preferable to measure with a dynamic light scattering particle size analyzer (DLS) from the target particle size to obtain a more accurate value. By measuring the particle size distribution using these measurement methods, the particle size D50 can be calculated. D50 is a value also called the median diameter, and it is the particle size of the median of the particle distribution, corresponding to a cumulative frequency of 50%.

[0044] Next, a "first grinding step" is performed to grind the particles in the sol particle liquid (a liquid in which the particles are dispersed in the dispersion medium). The grinding method in the first grinding step is not particularly limited, but for example, the method described in Japanese Patent Publication No. 7182358 may be used. Among these, high-pressure medialess grinding is preferred. The pressure in the first grinding step is not particularly limited, but for example, it may be 30 MPa or more, 50 MPa or more, 70 MPa or more, 100 MPa or more, or 150 MPa or more, and for example, it may be 350 MPa or less, 300 MPa or less, 250 MPa or less, 200 MPa or less, or 180 MPa or less, and for example, it may be 30 to 350 MPa, 50 to 300 MPa, 70 to 250 MPa, 100 to 200 MPa, or 150 to 180 MPa. The particle size D50 of the condensate of the raw material containing the alkoxysilane after the first grinding step is not particularly limited, but may be, for example, 25 nm or more, 30 nm or more, 35 nm or more, 40 nm or more, or 50 nm or more, or for example, 350 nm or less, 300 nm or less, 250 nm or less, 200 nm or less, or 150 nm or less, or for example, 25 to 350 nm, 30 to 300 nm, 35 to 250 nm, 40 to 200 nm, or 50 to 150 nm.

[0045] Next, a "concentration step" is performed to concentrate the sol particle liquid after the first grinding step. The concentration method in the concentration step is not particularly limited; for example, heating or pressurization may be used, but pressurization is preferred. More specifically, for example, the liquid may be concentrated to a predetermined concentration by pressurization using a filter, or the liquid may be concentrated to a predetermined concentration by partially removing the dispersion medium by heating or the like. The filter is also not particularly limited, but examples include rotary ceramic membrane filters and cross-flow filters. An example of a rotary ceramic membrane filter is the product name "Mitsubishi Dynafilter (DyF)" manufactured by Mitsubishi Chemical Machinery Ltd. The concentration of particles of the condensate of the raw material containing the alkoxysilane in the sol particle liquid after the concentration step is not particularly limited, but may be, for example, 3.6% by weight or more, 4.0% by weight or more, 4.5% by weight or more, 5.0% by weight or more, or 5.5% by weight or more, or for example, 40% by weight or less, 30% by weight or less, 20% by weight or less, 18% by weight or less, or 15% by weight or less, or for example, 3.6 to 40% by weight, 4.0 to 30% by weight, 4.5 to 20% by weight, 5.0 to 18% by weight, or 5.5 to 15% by weight. The concentration of solids (solid components) in the sol particle liquid after the concentration step is not particularly limited, but may be, for example, 3.6% by weight or more, 3.8% by weight or more, 4.0% by weight or more, 4.1% by weight or more, or 4.2% by weight or more, or for example, 39% by weight or less, 38% by weight or less, 37% by weight or less, 36% by weight or less, or 35% by weight or less, or for example, 3.6 to 39% by weight, 3.8 to 38% by weight, 4.0 to 37% by weight, 4.1 to 36% by weight, or 4.2 to 35% by weight.

[0046] Next, a "second grinding step" is performed to further grind the particles in the sol particle liquid after the concentration step. At this time, in the method for producing the first dispersion of the present disclosure, at least one of the following conditions is met: either the viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the particles in the liquid after the second grinding step is greater than the concentration of the particles in the liquid after the first grinding step. In the method for producing the second dispersion of the present disclosure, at least one of the following conditions is met: either the viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the solids in the liquid after the second grinding step is greater than the concentration of the solids in the liquid after the first grinding step. The grinding method in the second grinding step is not particularly limited, but for example, the method described in Japanese Patent No. 7182358 may be used. Among these, high-pressure medialess grinding is preferred. The pressure in the second grinding step is not particularly limited, but may be, for example, 30 MPa or more, 50 MPa or more, 70 MPa or more, 100 MPa or more, or 150 MPa or more, or for example, 350 MPa or less, 300 MPa or less, 250 MPa or less, 200 MPa or less, or 180 MPa or less, or for example, 30 to 350 MPa, 50 to 300 MPa, 70 to 250 MPa, 100 to 200 MPa, or 150 to 180 MPa. From the viewpoint of properly achieving the particle size control effect by performing the grinding process, it is preferable that the pressure in the second grinding step is not too low, and from the viewpoint of suppressing the increase in refractive index due to the particle size becoming too small, it is preferable that the pressure in the second grinding step is not too high.The particle size D50 of the condensate of the raw material containing the alkoxysilane after the second grinding step may be, for example, 20 nm or more and 400 nm or less, for example, 25 nm or more, 30 nm or more, 35 nm or more, 40 nm or more, or 50 nm or more, for example, 350 nm or less, 300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, or 80 nm or less, for example, 25 to 350 nm, 30 to 300 nm, 35 to 250 nm, 40 to 200 nm, 50 to 150 nm, or 20 to 100 nm.

[0047] Furthermore, from the viewpoint of minimizing the haze value of the low refractive index layer produced from the dispersion of this disclosure, it is preferable that the particle size D50 of the condensate of the raw materials containing the alkoxysilane is not too large. However, if D50 is small, the viscosity of the dispersion of this disclosure tends to be low. In that case, the viscosity of the dispersion of this disclosure can be increased, for example, by increasing the concentration of the particles or the solid content in the dispersion of this disclosure. Also, from the viewpoint of transparency, it is preferable that the particle size D50 of the condensate of the raw materials containing the alkoxysilane is not too large.

[0048] Furthermore, a "liquid concentration adjustment step" is performed in which a dispersion medium is added to the sol particle liquid after the second grinding step to adjust the liquid concentration, thereby producing the dispersion liquid of the present disclosure. At this time, the viscosity of the dispersion liquid is not particularly limited, but for example, it may be set to 4 mPa·s or more and less than 5000 mPa·s. In order to ensure the film thickness of the low refractive index layer, it is preferable that the viscosity of the dispersion liquid is not too low. In order to prevent large variations in the film thickness of the low refractive index layer (making it impossible to achieve uniformity of in-plane film thickness) or cracks from occurring in the low refractive index layer during drying, which would prevent the formation of the low refractive index layer itself, it is preferable that the viscosity of the dispersion liquid is not too high. The viscosity of the dispersion of this disclosure may be, for example, 5 mPa·s or more, 6 mPa·s or more, 7 mPa·s or more, 8 mPa·s or more, 9 mPa·s or more, 10 mPa·s or more, 11 mPa·s or more, 12 mPa·s or more, 13 mPa·s or more, 14 mPa·s or more, 15 mPa·s or more, 16 mPa·s or more, 17 mPa·s or more, 18 mPa·s or more, or 20 mPa·s or more, for example, 5000 mPa·s or less, 4000 mPa·s or less, 3500 mPa·s The following are also possible ranges: 3000 mPa·s or less, 2000 mPa·s or less, 1000 mPa·s or less, 500 mPa·s or less, 400 mPa·s or less, 300 mPa·s or less, 200 mPa·s or less, 100 mPa·s or less, 50 mPa·s or less, 40 mPa·s or less, 30 mPa·s or less, or 28 mPa·s or less. For example, the ranges may be 16 to 5000 mPa·s, 17 to 4000 mPa·s, 18 to 3500 mPa·s, or 20 to 3000 mPa·s. In this case, the concentration of particles of the condensate of the raw material containing the alkoxysilane in the dispersion is, for example, 3.5% by weight or more, which is within the range of the dispersion produced by the first dispersion production method of this disclosure. From the viewpoint of ensuring a sufficient film thickness of the low refractive index layer, it is preferable that the concentration of particles of the condensate of the raw material containing alkoxysilane in the dispersion of this disclosure is not too low. Furthermore, in order to prevent large variations in the film thickness of the low refractive index layer (making it impossible to achieve uniformity of in-plane film thickness) or the occurrence of cracks in the low refractive index layer during drying, which prevents the formation of the low refractive index layer itself, it is preferable that the concentration of particles of the condensate of the raw material containing alkoxysilane in the dispersion is not too high.The concentration of particles of the condensate of the raw materials containing the alkoxysilane in the dispersion of the present disclosure may be, for example, 3.6% by weight or more, 4.0% by weight or more, 4.5% by weight or more, 5.0% by weight or more, 5.5% by weight or more, or 6% by weight or more, for example, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 12% by weight or less, 10% by weight or less, 8% by weight or less, or 6% by weight or less, for example, 3.6 to 40% by weight, 4.0 to 35% by weight, 4.5 to 30% by weight, 5.0 to 25% by weight, 5.5 to 20% by weight, or 6.0 to 12.0% by weight. The concentration of solids (solid components) in the sol particle liquid after the concentration step is not particularly limited, but should be, for example, 3.5% by weight or more, which is within the range of the dispersion produced by the second dispersion production method of the present disclosure. The concentration of solids in the dispersion of this disclosure is preferably not too low from the viewpoint of ensuring the thickness of the low refractive index layer. The concentration of solids in the dispersion of this disclosure is also preferably not too high from the viewpoint of preventing or suppressing the large variation in the thickness of the low refractive index layer (making it impossible to achieve uniformity of in-plane film thickness) and the occurrence of cracks in the low refractive index layer during drying, which prevents the formation of the low refractive index layer itself. The concentration of solids in the dispersion of this disclosure may be, for example, 3.6% by weight or more, 3.8% by weight or more, 4.0% by weight or more, 4.1% by weight or more, 4.2% by weight or more, or 6.0% by weight or more, for example, 39% by weight or less, 38% by weight or less, 37% by weight or less, 36% by weight or less, 35% by weight or less, 15% by weight or less, 12% by weight or less, 10% by weight or less, 8% by weight or less, or 6% by weight or less, for example, 3.6 to 39% by weight, 3.8 to 38% by weight, 4.0 to 37% by weight, 4.1 to 36% by weight, 4.2 to 35% by weight, or 6.0 to 12.0% by weight. In addition, a crosslinking aid (also called a crosslinking agent), a catalyst, etc., for promoting crosslinking between particles of the condensate of the raw materials containing the alkoxysilane and for use in producing a low refractive index layer may be added together with the dispersion medium. The aforementioned crosslinking bond is not particularly limited, but for example, it may be a bond formed by covalent bonding between particles of the condensate of the raw material containing the alkoxysilane, either directly or via the crosslinking aid.The crosslinking aid is not particularly limited, but may be, for example, a substance having multiple functional groups that can form covalent bonds with particles of the condensate of the raw materials containing the alkoxysilane. Specifically, the crosslinking aid may be, for example, bis(trimethoxysilyl)alkylene. The bis(trimethoxysilyl)alkylene may be, for example, bis(trimethoxysilyl)hexane. Other examples of the crosslinking aid are not particularly limited, but are, for example, as described in Japanese Patent Publication No. 7182358. The concentration of the crosslinking aid in the dispersion of this disclosure is not particularly limited, but is, for example, as described in Japanese Patent Publication No. 7182358. The catalyst is not particularly limited, and may be, for example, a photoactive catalyst or a thermally active catalyst, or an acid catalyst or a base catalyst. In addition to or instead of the catalyst, a substance that generates a catalyst (catalyst generator) may be used. For example, in addition to or instead of the photoactive catalyst, a substance that generates a catalyst by light (photocatalyst generator) may be used, or in addition to or instead of the thermally activated catalyst, a substance that generates a catalyst by heat (thermal catalyst generator) may be used. The photocatalyst generator is not particularly limited, but examples include a photobase generator (a substance that generates a basic catalyst by light irradiation), a photoacid generator (a substance that generates an acidic catalyst by light irradiation), and so on, with photobase generators being preferred.Examples of the aforementioned photobase generators include 9-anthrylmethyl N,N-diethylcarbamate (trade name WPBG-018), (E)-1-[3-(2-hydroxyphenyl)-2-propenoyl]piperidine (trade name WPBG-027), 1-(anthraquinon-2-yl)ethyl imidazolecarboxylate (trade name WPBG-140), 2-nitrophenylmethyl 4-methacryloyloxypiperidine-1-carboxylate (trade name WPBG-165), and 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidium Examples include 2-(3-benzoylphenyl)propionate (trade name WPBG-266), 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidium n-butyltriphenyl borate (trade name WPBG-300), and 1,5,7-triazabicyclo[4.4.0]deca-5-ene 2-(9-oxoxanthene-2-yl)propionic acid (Tokyo Chemical Industries, Ltd.), and compounds containing 4-piperidine methanol (trade name HDPD-PB100: manufactured by Heraeus). Note that all trade names containing "WPBG" are trade names of Wako Pure Chemical Industries, Ltd. Examples of photoacid generators include aromatic sulfonium salts (trade name SP-170: ADEKA), triarylsulfonium salts (trade name CPI101A: Sunapro), and aromatic iodonium salts (trade name Irgacure250: Ciba Japan). The concentration of the catalyst or catalyst generator in the dispersion of this disclosure is not particularly limited, but is, for example, as described in Japanese Patent Publication No. 7182358.

[0049] The dispersion of the present disclosure can be manufactured in the manner described above. However, the method for manufacturing the dispersion of the present disclosure is not limited thereto, and any manufacturing method is acceptable as long as it satisfies the conditions of the dispersion of the present disclosure. For example, the method for manufacturing the dispersion of the present disclosure may or may not include steps other than the "first grinding step," "concentration step," and "second grinding step." For example, the liquid concentration adjustment step may or may not be performed as needed, and the grinding step is not limited to the two steps of the first grinding step and the second grinding step, but may consist of three or more steps.

[0050] Furthermore, the method for producing the dispersion of this disclosure may be such that, for example, the pressure during the first grinding step and the pressure during the second grinding step are the same, and all of the following relational equations (1) to (3) are satisfied. This has the effect of suppressing light scattering caused by particle size when light is guided to the hyporefractory layer, for example. Particle size D50 after the concentration process > Particle size D50 after the first grinding process Particle size D50 after the concentration process > Particle size D50 after the second grinding process The particle size D50 of the particles after the first grinding is greater than or equal to the particle size D50 of the particles after the second grinding.

[0051] [2. Low refractive index layer and method for manufacturing the same] The low refractive index layer of the present disclosure is characterized by being obtained by coating and drying the dispersion of the present disclosure, as described above. The layer obtained by coating and drying the dispersion of the present disclosure may be subjected to, for example, heating or light irradiation. By heating or light irradiation, for example, the particles of the condensate of the raw material containing the alkoxysilane can be crosslinked together directly or via the crosslinking aid, thereby increasing the strength.

[0052] The low refractive index layer of this disclosure may be manufactured, for example, by coating the dispersion of this disclosure onto a substrate such as a film and drying it. The film may be, for example, a resin film. Generally, materials with relatively small thickness are called "films" and those with relatively large thickness are called "sheets" to distinguish them, but in this disclosure, there is no particular distinction between "films" and "sheets". The substrate is not particularly limited, and preferably, but is not limited to, thermoplastic resin substrates, glass substrates, inorganic substrates represented by silicon, plastics molded from thermosetting resins, semiconductor devices, carbon fiber materials represented by carbon nanotubes, etc.

[0053] The method for manufacturing the low refractive index layer of this disclosure is not particularly limited and may be used, for example, in a manner similar to that described in International Publication No. 2019 / 065999 or International Publication No. 2019 / 065803.

[0054] The low refractive index layer of this disclosure may be, for example, a void layer having voids. Alternatively, the low refractive index layer of this disclosure may be, for example, a porous material in which microporous particles are chemically bonded to each other.

[0055] The low refractive index layer of this disclosure may have a thickness of, for example, 500 nm or more, 700 nm or more, 800 nm or more, 1000 nm or more, nm or more, or 2000 nm or more, for example, 10000 nm or less, 8000 nm or less, 5000 nm or less, 4000 nm or less, or 3000 nm or less, for example, 500 to 10000 nm, 700 to 8000 nm, 800 to 5000 nm, 1000 to 4000 nm, or 2000 to 3000 nm. The low refractive index layer of the present invention may have a porosity of, for example, 30 volume% or more, 35 volume% or more, 40 volume% or more, 45 volume% or more, or 50 volume% or more, or for example, 90 volume% or less, 80 volume% or less, 70 volume% or less, or 60 volume% or less, or for example, 30 to 90 volume%, 35 to 80 volume%, 40 to 70 volume%, or 50 to 60 volume%. The low refractive index layer of the present invention may have a refractive index of, for example, 1.05 or more, 1.10 or more, or 1.13 or more, or for example, 1.35 or less, 1.30 or less, or 1.25 or less, or for example, 1.05 to 1.35, 1.10 to 1.30, or 1.13 to 1.25.

[0056] In the low refractive index layer of this disclosure, the porosity can be measured by the following method.

[0057] (Method for measuring void ratio) If the layer being measured for porosity is a single layer containing only voids, the ratio (volume ratio) of the layer's constituent material to air can be calculated using standard methods (for example, by measuring weight and volume to calculate density), and thus the porosity (volume %) can be calculated. Furthermore, since there is a correlation between refractive index and porosity, the porosity can also be calculated from the refractive index value of the layer, for example. Specifically, for example, the porosity can be calculated from the refractive index value measured with an ellipsometer using the Lorentz-Lorenz formula.

[0058] In this disclosure, the refractive index of the low refractive index layer is the refractive index value at a wavelength of 550 nm, measured and calculated by the method described below.

[0059] (Method for measuring refractive index) After forming a low refractive index layer on a glass light guide plate, a laser beam (λ=407nm) is incident from the glass light guide plate side using a prism coupler (manufactured by Metricon), and the refractive index at 407nm is calculated from the measured total reflection angle. Furthermore, the measured refractive index at 407nm is converted to the refractive index at 550nm from the wavelength dispersion of the low refractive index layer alone, which is calculated separately using an ellipsometer (manufactured by JAWoollam), and this converted value is taken as the refractive index of the low refractive index layer.

[0060] The low refractive index layer of this disclosure preferably has a thickness variation of, for example, 20% or less, 18% or less, 16% or less, 15% or less, or 10% or less, and the lower limit is not particularly limited, but may be, for example, 0 or a value greater than 0. The thickness variation refers to the in-plane film thickness variation of the low refractive index layer when a low refractive index layer of 1.25 or less is formed by spin coating on a light guide plate with a diameter or short side of 20 cm or less made of glass or resin with a surface roughness Rz of 50 nm or less using the dispersion of this disclosure. In this disclosure, the in-plane film thickness variation of the low refractive index layer is an index obtained by comparing the standard deviation of the measured values ​​of the film thickness at five points in the plane with the average film thickness.

[0061] [3. Optical components and optical devices] The optical member of this disclosure is characterized by including the low refractive index layer of the present invention, as described above. The optical member of this disclosure may or may not include components other than the low refractive index layer of the present invention.

[0062] The optical member of this disclosure may be, for example, a laminate in which the low refractive index layer of the present invention is laminated on a substrate. The substrate is not particularly limited, but may be as described above.

[0063] The optical component of this disclosure may be, for example, a light guide plate with a low refractive index layer, wherein the low refractive index layer of this disclosure is laminated on a light guide plate. In this case, other layers such as adhesive layers may exist between the light guide plate and the low refractive index layer of this disclosure, but it is preferable that the low refractive index layer of this disclosure is laminated directly on the light guide plate without any other layers in between. In this case, for example, the low refractive index layer of this disclosure can be manufactured by coating the light guide plate with the dispersion of this disclosure and drying it using the method described above.

[0064] The optical components of this disclosure are not limited to light guide plates, but may also include, for example, polarizing plates, phase difference films, reflective polarizers, brightness-enhancing films, diffusion films, dye-containing layers, or layers or films having transparent and opaque optical functions.

[0065] The optical device described herein is not particularly limited, but may be, for example, an image display device or an illumination device. Examples of image display devices include liquid crystal displays, organic EL (Electro Luminescence) displays, and micro-LED (Light Emitting Diode) displays. Examples of illumination devices include organic EL lighting. [Examples]

[0066] Next, embodiments of the present disclosure will be described. However, the present disclosure is not limited to the following embodiments.

[0067] In the following reference examples, examples, and comparative examples, the number of parts (relative amount used) of each substance is in parts by mass (parts by weight) unless otherwise specified. In the following reference examples, examples, and comparative examples, the adhesive used is the adhesive (adhesive composition) described later. In the following reference examples, examples, and comparative examples, "adhesive layer" corresponds to "adhesive bonding layer." That is, in the following reference examples, examples, and comparative examples, "adhesive layer" and "adhesive bonding layer" are synonymous unless otherwise specified.

[0068] <Method for measuring the concentration of coating solution> The total concentration of solids (components other than the dispersion medium) in the coating solution, or the concentration (by weight) of particles of the condensate of the raw material containing alkoxysilane, was calculated from the ratio of the total weight (mass) of the coating solution to the total weight (mass) of the solids in the coating solution or the weight (mass) of particles of the condensate of the raw material containing alkoxysilane.

[0069] <Method for measuring the viscosity of coating liquid> The viscosity of the coating solution was measured at a measurement temperature of 25°C using an E-type viscometer with a 1° cone rotor.

[0070] <Method for measuring refractive index> The refractive index was measured using the refractive index measurement method described above.

[0071] <Method for measuring particle size> The particle size D50 of the condensate of raw materials containing alkoxysilane was measured by the method described above. As mentioned above, D50 is also called the median diameter and is the particle size of the median of the particle distribution, corresponding to a cumulative frequency of 50%.

[0072] <Method for measuring film thickness> The film thickness and its variation of the low refractive index layer were measured as follows: The thickness of the low refractive index layer formed on glass was measured at five points in the plane using a spectroscopic ellipsometer (manufactured by JA Woolam), and the mean and standard deviation were calculated. The ratio of this standard deviation to the mean was calculated and this value was defined as the variation.

[0073] <Method for evaluating light guide properties> The state of a glass plate substrate, which has a low refractive index layer formed on it, when light is introduced from the edge using an LED and guided through, was visually evaluated according to the following criteria. Cloudiness present during light guidance. NG (×) No clouding during light guidance (remains transparent) OK (○)

[0074] <Method for measuring haze value> A 100mm x 100mm laminate (void layer / glass substrate) was used as the measurement sample. The measurement sample was placed in a spectroscopic haze meter (manufactured by Nippon Denshoku Industries Co., Ltd.: SH7000) and the haze value was measured. More specifically, the diffuse transmittance and total light transmittance were measured, and the haze value calculated from these values ​​using the following formula was used as the measured haze value. Haze value (%) = [Diffuse transmittance (%) / Total light transmittance (%)] × 100 (%)

[0075] [Reference Example 1: Manufacturing of a gel pulverizing solution for forming a low refractive index layer] A gel pulverizing liquid (sol particle liquid) for forming a low refractive index layer was prepared as follows.

[0076] (1) Gelation of silicon compounds Mixture A was prepared by dissolving 9.5 kg of methyltrimethoxysilane (MTMS), a precursor of silicon compounds, in 22 kg of dimethyl sulfoxide (DMSO). To this mixture A, 5 kg of 0.01 mol / L aqueous oxalic acid solution was added, and the mixture was stirred at room temperature for 30 minutes to hydrolyze the MTMS and produce mixture B containing tris(hydroxy)methylsilane.

[0077] To 55 kg of DMSO, 3.8 kg of 28% by weight aqueous ammonia and 2 kg of pure water were added. Then, the above mixture B was added, and the mixture was stirred at room temperature for 15 minutes to gel tris(hydroxy)methylsilane, obtaining mixture C containing a gel-like silicon compound.

[0078] (2) Aging process The mixed solution C containing the gel-like silicon compound prepared as described above was poured into a 30cm x 30cm x 5cm stainless steel container and incubated at 40°C for 20 hours to perform the maturation process.

[0079] (3) Grinding Next, isobutyl alcohol, the substitution solvent, was poured onto the gel synthesized in the stainless steel container. Then, the cutting blade of a cutting jig was slowly inserted into the gel from above, and the gel was cut into a rectangular parallelepiped measuring 1.5 cm × 2 cm × 5 cm. The cut gel was transferred to another container, and while being careful not to disturb the shape of the gel, isobutyl alcohol was added in an amount four times the volume of the gel. After standing for 6 hours, solvent replacement was performed four times. The gel (gel-like silicon compound) was then pulverized using a continuous emulsification dispersion machine (Milder MDN304, manufactured by Taiheiyo Kiko Co., Ltd.) to obtain a coarse pulverization liquid. Further pulverization was performed using a high-pressure medialess pulverizer (Starburst HJP-25005, manufactured by Sugino Machine Co., Ltd.) under a pressure of 100 MPa. In this way, an isobutyl alcohol dispersion (liquid containing pulverized gel) in which nanometer-sized particles (pulverized gel) were dispersed was obtained.

[0080] [Example 1] In Reference Example 1, IBA (isobutyl alcohol) was added to the gel pulverized liquid to adjust the concentration of particles of the condensate of the raw material containing alkoxysilane to 3.5% by weight. Next, nano-pulverization was performed on this gel pulverized liquid using Starburst (product name of Sugino Machine Co., Ltd.) under a high pressure of 150 MPa, adjusting the pulverization time so that the particle size D50 of the pulverized particles after pulverization was 150 nm, thereby obtaining a nano-pulverized liquid with a concentration of particles of the condensate of the raw material containing alkoxysilane at 3.5% by weight (first pulverization step). Next, the liquid was concentrated using Mitsubishi Dynafilter (DyF) (product name of Mitsubishi Chemical Machinery Ltd.) until the concentration of particles of the condensate of the raw material containing alkoxysilane reached 5.6% by weight (concentration step). Next, nano-pulverization was performed again using Starburst under a high pressure of 150 MPa, adjusting the pulverization time so that the particle size D50 of the pulverized particles after pulverization was 130 nm (second pulverization step). The measurement results for the concentration, viscosity, and particle size of the liquids obtained in each of these steps are shown in Table 1 below. After the second grinding step, 0.22 g of bis(trimethoxysilyl)hexane, a crosslinking aid, and 0.22 g of the photobase catalyst WPBG-266 (Wako) were added to 100 g of the liquid, and then IBA (isobutyl alcohol) was added to adjust the total solid content concentration of the liquid to 4.2% by weight (the concentration of particles of the condensate of the raw materials containing alkoxysilane was 3.86% by weight), thereby producing the dispersion liquid of this disclosure. The dispersion liquid was then formed into a film on a glass plate by spin coating, dried, and then subjected to a pressure of 350 mJ / cm². 2 The low refractive index layer of this disclosure was manufactured by crosslinking the particles of the condensate of the raw material containing alkoxysilane by UV irradiation at (@360nm). The optical properties and appearance evaluation of the manufactured low refractive index layer are summarized in Table 1 below.

[0081] [Example 2] The dispersion and low refractive index layer of the present disclosure were produced by the same procedure as in Example 1, except that in the first grinding step the grinding time was adjusted so that the particle size D50 of the particles after grinding was 80 nm, in the second grinding step the grinding time was adjusted so that the particle size D50 of the particles after grinding was 50 nm, and thereafter the amount of IBA added was changed to adjust the total solid content concentration of the liquid to 9.5% by weight (the concentration of particles of the condensate of the raw materials containing alkoxysilane was 9.03% by weight).

[0082] [Example 3] The dispersion and low refractive index layer of the present disclosure were produced by the same procedure as in Example 1, except that in the first grinding step the grinding time was adjusted so that the particle size D50 of the particles after grinding was 80 nm, in the second grinding step the grinding time was adjusted so that the particle size D50 of the particles after grinding was 65 nm, and thereafter the amount of IBA added was changed to adjust the total solid content concentration of the liquid to 8.0% by weight (the concentration of particles of the condensate of the raw materials containing alkoxysilane was 7.73% by weight).

[0083] [Comparative Example 1] The low refractive index layer was manufactured in the same manner as in Example 1, except that the second grinding step was omitted and the film (low refractive index layer) was formed directly after the concentration step.

[0084] [Comparative Example 2] A low refractive index layer was produced in the same manner as in Example 1, except that the order of the concentration step and the second grinding step was reversed, and the concentration step was performed after the second grinding step.

[0085] [Comparative Example 3] When the concentration process was performed before the first grinding process, frequent clogging occurred, and the concentration process could not be completed. As a result, the low refractive index layer could not be formed.

[0086] The optical properties and appearance of the film (low refractive index layer) of the low refractive index layers of each example and comparative example manufactured as described above were evaluated using the method described above. The evaluation results are summarized in Table 1 below. In Table 1 below, "Viscosity after the first grinding step" represents the viscosity of the liquid in each example and comparative example after the first grinding step. "Concentration after the first grinding step" represents the total concentration of solids in the liquid in each example and comparative example after the first grinding step. "Particle concentration after the first grinding step" represents the concentration of siloxane condensate particles in the liquid in each example and comparative example after the first grinding step. "Particle size D50 after the first grinding step" represents the particle size D50 of siloxane condensate particles in the liquid in each example and comparative example after the first grinding step. "Viscosity after the concentration step" represents the viscosity of the liquid in each example and comparative example after the concentration step. "Concentration after the concentration step" represents the total concentration of solids in the liquid in each example and comparative example after the concentration step. "Particle concentration after concentration" represents the concentration of siloxane condensate particles in the liquid in each of the above examples and comparative examples after the concentration process. "Particle size D50 after concentration" represents the particle size D50 of siloxane condensate particles in the liquid in each of the above examples and comparative examples after the concentration process. "Viscosity after second grinding" represents the viscosity of the liquid in each of the above examples and comparative examples after the second grinding process. "Concentration after second grinding" represents the total concentration of solids in the liquid in each of the above examples and comparative examples after the second grinding process. "Particle concentration after second grinding" represents the concentration of siloxane condensate particles in the liquid in each of the above examples and comparative examples after the second grinding process. "Particle size D50 after second grinding" represents the particle size D50 of siloxane condensate particles in the liquid in each of the above examples and comparative examples after the second grinding process. "Refractive index of low refractive index layer" represents the refractive index of the low refractive index layer produced in each of the above examples and comparative examples. "Thickness of the low refractive index layer" represents the thickness of the low refractive index layer manufactured in each of the above examples and comparative examples. "Light guiding properties" represents the evaluation results of the light guiding properties of the low refractive index layer manufactured in each of the above examples and comparative examples. "Haze" represents the haze value of the low refractive index layer manufactured in each of the above examples and comparative examples.

[0087] [Table 1]

[0088] As shown in Table 1 above, the dispersions (coating liquids) of the present disclosure produced by the dispersion manufacturing method of the present disclosure in Examples 1 to 3 were able to secure a sufficiently large film thickness when a low refractive index layer was formed. Furthermore, in Example 1, it was confirmed that the low refractive index layer had good light-guiding properties, resulting in the production of a low refractive index layer with small film thickness variations (in-plane film thickness uniformity was achieved). In contrast, in Comparative Example 1, which did not perform the second grinding step, and in Comparative Example 2, which did not perform the concentration step and the second grinding step in the order of the present disclosure, it was confirmed that the low refractive index layer had poor light-guiding properties, resulting in large film thickness variations (in-plane film thickness uniformity could not be achieved). In addition, in Comparative Example 3, which did not follow the order of the steps of the present disclosure and performed the concentration step before the first grinding step, liquid clogging occurred frequently, and the concentration step could not be completed, and as a result, the low refractive index layer could not be formed.

[0089] Although the present disclosure has been described above with reference to embodiments and examples, the present disclosure is not limited to the embodiments and examples described above. Various modifications to the structure and details of the present disclosure are possible, as can be understood by those skilled in the art within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0090] This disclosure may also be presented, for example, as shown in the following appendix. However, the following appendix is ​​illustrative, and this disclosure is not limited to these forms.

[0091] (Note 1) A method for producing a dispersion liquid in which particles are dispersed in a dispersion medium, The aforementioned particles are condensates of raw materials containing alkoxysilane, The first grinding step, the concentration step, and the second grinding step are carried out in this order. The first grinding step is a step of grinding the particles in the liquid in which the particles are dispersed in the dispersion medium, The aforementioned concentration step is a step of concentrating the liquid, The second grinding step is a step of further grinding the particles in the liquid that were ground in the first grinding step, The viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the particles in the liquid after the second grinding step is greater than the concentration of the particles in the liquid after the first grinding step. A method for manufacturing, characterized in that the concentration of the particles in the manufactured dispersion is 3.5% by weight or more. (Note 2) A method for producing a dispersion liquid in which solid components containing particles are dispersed in a dispersion medium, The aforementioned particles are condensates of raw materials containing alkoxysilane, The first grinding step, the concentration step, and the second grinding step are carried out in this order. The first grinding step is a step of grinding the particles in the liquid in which the solid content is dispersed in the dispersion medium, The aforementioned concentration step is a step of concentrating the liquid, The second grinding step is a step of further grinding the particles in the liquid that were ground in the first grinding step, The viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the solids in the liquid after the second grinding step is greater than the concentration of the solids in the liquid after the first grinding step. A manufacturing method characterized in that the concentration of the solid content in the manufactured dispersion is 3.5% by weight or more. (Note 3) The pressure during the first grinding step is equal to or equal to or less than the pressure during the second grinding step, and A manufacturing method described in Appendix 1 or 2 that satisfies all of the following relational expressions (1) to (3). Particle size D50 after the concentration process > Particle size D50 after the first grinding (1) Particle size D50 after the concentration process > Particle size D50 after the second grinding (2) (3) The particle size D50 of the particles after the first grinding is greater than or equal to the particle size D50 of the particles after the second grinding. (Note 4) The pressure during the first grinding step is greater than the pressure during the second grinding step, and A manufacturing method described in Appendix 1 or 2 that satisfies all of the following relational expressions (1) to (3). Particle size D50 after the concentration process > Particle size D50 after the first grinding (1) Particle size D50 after the concentration process > Particle size D50 after the second grinding (2) The particle size D50 of the particles after the first grinding is ≤ the particle size D50 of the particles after the second grinding. (3) (Note 5) The manufacturing method according to any one of the appendices 1 to 4, wherein the pressure in the first grinding step is 50 MPa or more. (Note 6) A dispersion characterized by being manufactured by the manufacturing method described in any of the appendices 1 to 5. (Note 7) A low refractive index layer characterized by being obtained by coating and drying the dispersion described in Appendix 6. (Note 8) A low refractive index layer as described in Appendix 7, having a refractive index of 1.25 or less. (Note 9) A low refractive index layer as described in Appendix 7 or 8, having a thickness of 800 nm or more. (Note 10) An optical component characterized by including a low refractive index layer as described in any of appendices 7 to 9. (Note 11) An optical device characterized by including the optical component described in Appendix 10. (Note 12) A step of producing the dispersion by the manufacturing method described in any of Appendix 1 to 5, A method for producing a low refractive index layer, comprising the steps of coating a substrate with the dispersion liquid and drying the coated dispersion liquid. (Note 13) The manufacturing method described in Appendix 12, wherein the refractive index of the low refractive index layer produced is 1.25 or less. (Note 14) The manufacturing method according to Appendix 12 or 13, wherein the thickness of the low refractive index layer produced is 800 nm or more. (Note 15) A method for manufacturing an optical component including a low refractive index layer, characterized in that the low refractive index layer is manufactured by the manufacturing method described in any of appendices 12 to 14. (Note 16) A method for manufacturing an optical device including an optical component, characterized in that the optical component is manufactured by the manufacturing method described in Appendix 15. [Industrial applicability]

[0092] As described above, the present disclosure provides a method for manufacturing a dispersion that enables securing the film thickness of a low refractive index layer and achieving uniformity of the in-plane film thickness, a dispersion, a low refractive index layer, an optical component, an optical device, a method for manufacturing a low refractive index layer, a method for manufacturing an optical component, and an optical device. The applications of the present disclosure are not particularly limited. For example, the optical device of the present disclosure is not particularly limited and includes image display devices, lighting devices, etc. Examples of the image display device include liquid crystal displays, organic EL displays, micro-LED displays, etc. Examples of the lighting device include organic EL lighting, etc.

[0093] This application claims priority based on Japanese Patent Application No. 2024-026039, filed on 22 February 2024, and incorporates all of its disclosures herein.

Claims

1. A method for producing a dispersion liquid in which particles are dispersed in a dispersion medium, The aforementioned particles are condensates of raw materials containing alkoxysilane, The first grinding step, the concentration step, and the second grinding step are carried out in this order. The first grinding step is a step of grinding the particles in the liquid in which the particles are dispersed in the dispersion medium, The aforementioned concentration step is a step of concentrating the liquid, The second grinding step is a step of further grinding the particles in the liquid that were ground in the first grinding step, The viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the particles in the liquid after the second grinding step is greater than the concentration of the particles in the liquid after the first grinding step. A method for manufacturing, characterized in that the concentration of the particles in the manufactured dispersion is 3.5% by weight or more.

2. A method for producing a dispersion liquid in which solid components containing particles are dispersed in a dispersion medium, The aforementioned particles are condensates of raw materials containing alkoxysilane, The first grinding step, the concentration step, and the second grinding step are carried out in this order. The first grinding step is a step of grinding the particles in the liquid in which the solid content is dispersed in the dispersion medium, The aforementioned concentration step is a step of concentrating the liquid, The second grinding step is a step of further grinding the particles in the liquid that were ground in the first grinding step, The viscosity of the liquid after the second grinding step is greater than the viscosity of the liquid after the first grinding step, or the concentration of the solids in the liquid after the second grinding step is greater than the concentration of the solids in the liquid after the first grinding step. A manufacturing method characterized in that the concentration of the solid content in the manufactured dispersion is 3.5% by weight or more.

3. The pressure during the first grinding step is equal to or equal to or less than the pressure during the second grinding step, and A manufacturing method according to claim 1 or 2, which satisfies all of the following relational formulas (1) to (3). Particle size D50 after the concentration process > Particle size D50 after the first grinding (1) The particle size D50 after the concentration process > the particle size D50 after the second grinding (2) (3) The particle size D50 of the particles after the first grinding is greater than or equal to the particle size D50 of the particles after the second grinding.

4. The pressure during the first grinding step is greater than the pressure during the second grinding step, and A manufacturing method according to claim 1 or 2, which satisfies all of the following relational formulas (1) to (3). Particle size D50 after the concentration process > Particle size D50 after the first grinding (1) The particle size D50 after the concentration process > the particle size D50 after the second grinding (2) The particle size D50 of the particles after the first grinding is ≤ the particle size D50 of the particles after the second grinding. (3)

5. The manufacturing method according to claim 1 or 2, wherein the pressure in the first grinding step is 50 MPa or more.

6. A step of producing the dispersion by the manufacturing method described in claim 1 or 2, A method for producing a low refractive index layer, comprising the steps of coating a substrate with the dispersion liquid and drying the coated dispersion liquid.

7. The manufacturing method according to claim 6, wherein the refractive index of the low refractive index layer produced is 1.25 or less.

8. The manufacturing method according to claim 6, wherein the thickness of the low refractive index layer produced is 800 nm or more.

9. A method for manufacturing an optical component including a low refractive index layer, characterized in that the low refractive index layer is manufactured by the manufacturing method described in claim 6.

10. A method for manufacturing an optical device including an optical component, characterized in that the optical component is manufactured by the manufacturing method described in claim 9.

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