TW201814005A - Light diffusion transmission sheet capable of improving illuminance properties of the light diffusion transmission sheet by providing high illuminance composite particles - Google Patents

Abstract

A light diffusion-transmission sheet (1) of the present invention is provided with a resin (10) having base material and composite particles (20). The composite particles (20) comprise a resin binding agent (21) having a refractive index higher than 1.43, and micro-particles (22) encapsulated inside the resin binding agent (21). The composite particles (20) are dispersed in the base resin (10). The micro-particles (22) comprise a first micro-particle (22a) having a refractive index below 1.43.

Description

   Light diffusion transmission sheet   

The present invention relates to a light diffusion and transmission sheet.

With the improvement of the image quality of the liquid crystal display, in order to spatially homogenize the light emitted from the backlight device of the liquid crystal display, the demand for a light diffusion transmission sheet with higher light diffusion characteristics is increasing. In addition, from the standpoint of reducing energy consumption, the demand for light-diffusing transmissive sheets with higher brightness characteristics is also increasing.

Patent Document 1 describes a resin including a base material and a light diffusion and transmission sheet of silicon oxide composite particles dispersed in the resin. The silicon oxide composite particles include titanium oxide fine particles having an average particle diameter of 100 nm or less. The light-diffusion transmissive sheet described in Patent Document 1 exhibits high total light transmittance and haze. Furthermore, the refractive index of titanium oxide is greater than that of silicon oxide.

Patent Document 2 describes an optical laminate having an internal scattering layer provided on a light-transmitting substrate. The internal scattering layer contains internal scattering particles. The average particle diameter of the internal scattering particles is 1 to 10 μm, and the inner particles include fine particles composed of organic materials and / or inorganic materials with an average particle diameter of 5 to 300 nm. The refractive index n _A of the microparticles enclosed in the internal scattering particles is larger than the refractive index n _B of components other than the microparticles contained in the internal scattering particles.

Patent Document 3 describes a transmissive screen for viewing an image projected from a projector. The transmissive screen has a light diffusing layer containing light diffusing particles and a xerogel. The light-diffusing fine particles are carried by a xerogel. As a result, the xerogel voids (air having a refractive index of 1.0) exist on the surface of the light-diffusing fine particles, and the relative refractive index of the light-diffusing fine particles with respect to air becomes extremely high. Therefore, efficient light diffusion of the light-diffusing fine particles can be achieved. As a result, it is possible to provide a penetrating screen capable of viewing an image projected from a projector with a wide viewing angle and excellent visibility from both sides of the screen. Patent Document 3 describes that as the light-diffusing fine particles, composite particles obtained by using organic fine particles and a small amount of inorganic fine particles, or composite particles obtained by using inorganic fine particles and a small amount of an organic polymer can be used. Examples of composite particles obtained by using organic fine particles and a small amount of inorganic fine particles include composite particles obtained by coating the surface of fine particles such as melamine resin or acrylic resin with inorganic fine particles such as silicon oxide. Furthermore, generally, the refractive index of melamine resin and acrylic resin is higher than that of silicon oxide.

Patent Document 4 describes a light diffusion plate including a light diffusion layer composed of a transparent substrate containing a transparent resin. The light diffusion layer contains first light diffusion particles and second light diffusion particles existing inside the transparent substrate. The refractive index of the second light diffusion particles is greater than the refractive index of the first light diffusion particles. The refractive index of the first light diffusion particle is 1.4 to 1.7, and the refractive index of the second light diffusion particle is greater than 2.

Patent Document 5 describes composite resin particles having a core-shell structure including a core composed of a first thermoplastic resin and a second thermoplastic resin different from the first thermoplastic resin. Shell made of resin and covering the core. The inorganic particles are localized in the outer shell of the composite resin particle and are contained in the outer shell. The composite resin particles can be used as a light scattering additive (light diffusing agent) for a flat panel display.

Patent Document 1: Japanese Patent Application Laid-Open No. 2014-48427

Patent Document 2: Japanese Patent Application Laid-Open No. 2009-42554

Patent Document 3: Japanese Patent Application Publication No. 2013-195548

Patent Document 4: Japanese Patent Application Laid-Open No. 2008-40479

Patent Document 5: Japanese Patent Application Laid-Open No. 2008-291253

According to the techniques described in Patent Documents 1 and 2, the fine particles enclosed in the composite particles have a relatively high refractive index. In addition, according to the technique described in Patent Document 3, it has been suggested that the surface of fine particles having a relatively high refractive index is coated with a material having a relatively low refractive index. However, these technologies are not necessarily conducive to improving the brightness of the light-diffusing and transmitting sheet in which the composite particles are dispersed. Further, in Patent Document 4, it is not described or suggested that the composite particles are dispersed in a transparent substrate.

Based on this situation, an object of the present invention is to provide a light-diffusing and transmissive sheet having higher brightness characteristics by including composite particles that are advantageous for improving brightness.

The present invention provides a light-diffusing and transmitting sheet comprising: a base material resin; and composite particles containing a resin binder having a refractive index higher than 1.43 and fine particles enclosed in the resin binder, and dispersed The base material resin; and the fine particles include first fine particles having a refractive index of 1.43 or less.

The light-diffusion transmissive sheet has high brightness characteristics by containing the first particles having a refractive index of 1.43 or less in the particles contained in the resin adhesive having a refractive index higher than 1.43.

1, 201, 301‧‧‧‧light diffusion transmission sheet

10, 210, 310‧‧‧ Base resin

20, 220, 320‧‧‧ composite particles

21, 221‧‧‧ resin adhesive

22, 222‧‧‧ fine particles

22a‧‧‧The first particle

22b‧‧‧Second Particle

31‧‧‧Flat friction element

32‧‧‧ Heavy

40‧‧‧Support Desk

222a‧‧‧Magnesium fluoride fine particles (first fine particles)

222b‧‧‧Silicon oxide particles

320a‧‧‧ core

320b‧‧‧shell

321‧‧‧first resin adhesive

322‧‧‧Core Particles

322a‧‧‧ Low refractive index particles (first particles)

323‧‧‧Second resin adhesive

324‧‧‧shell particles

PH‧‧‧ High refractive index fine particles

PL‧‧‧ Low refractive index fine particles PL

PS‧‧‧Brightness Enhancement Film

Sa‧‧‧ Sample

FIG. 1 is a schematic cross-sectional view of a light diffusion and transmission sheet according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing the structure of a composite particle.

FIG. 3A is a light path diagram schematically showing light of high refractive index fine particles incident on the inside of composite particles.

FIG. 3B is a light path diagram schematically showing light of a low refractive index fine particle incident on the inside of the composite particle.

4 is a cross-sectional view schematically showing a structure of a composite particle according to a modification.

Fig. 5 is a schematic cross-sectional view of a light diffusion and transmission sheet according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view schematically showing a structure of a composite particle.

Fig. 7 is a schematic cross-sectional view of a light diffusion and transmission sheet according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view schematically showing a structure of a composite particle.

FIG. 9A is a light path diagram schematically showing light of high refractive index particles incident on the inside of the composite particle.

FIG. 9B is a light path diagram schematically showing light of a low refractive index particle incident on the inside of the composite particle.

FIG. 10 is a cross-sectional view schematically showing a structure of a composite fine particle according to a modification.

FIG. 11 is a graph showing the luminance characteristics of the light-diffusing and transmissive sheets of Examples and Comparative Examples.

FIG. 12 is a graph showing the haze ratios of the light diffusion and transmission sheets of the examples and comparative examples.

FIG. 13 is a side view showing a device for evaluating damage-imparting characteristics of samples of the light-diffusing and transmissive sheets of Examples and Comparative Examples.

FIG. 14 is a graph showing the luminance characteristics of the light diffusion and transmission sheets of the examples and comparative examples.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description is an example of the present invention, and the present invention is not limited by these.

<First Embodiment>

As shown in FIG. 1, the light diffusion and transmission sheet 1 of the present invention includes a base material resin 10 and composite particles 20. The composite particles 20 are dispersed in a base material resin 10. The base material resin 10 is not particularly limited, and is preferably a resin that has excellent dispersibility of the composite particles 20 and has transparency to visible light, weather resistance, moisture resistance, and heat resistance. Examples of the base material resin 10 include polyester polyols, linear polyesters, acrylic resins, amine resins, epoxy resins, melamine resins, silicone resins, urethane resins, Materials such as vinyl acetate resin, norbornene resin, and polycarbonate resin. Various thermosetting resins and various ultraviolet curing resins can also be used. It is also possible to appropriately add an isocyanate-based hardener and various dispersants to these resins. The light diffusion transmission sheet 1 may further include a substrate (not shown) such as a PET (polyethylene terephthalate) film, and the base material resin 10 in which the composite particles 20 are dispersed may be formed in a layered manner on the substrate.

As shown in FIG. 2, the composite particles 20 include a resin binder 21 and fine particles 22. The resin adhesive 21 has a refractive index higher than 1.43. The fine particles 22 are enclosed in a resin adhesive 21. The fine particles 22 include first fine particles 22a. The first fine particles 22a have a refractive index of 1.43 or less. As such, in the composite particles 20, the first fine particles 22a having a relatively low refractive index are enclosed in the resin adhesive 21 having a relatively high refractive index.

As shown in FIG. 3A, when light is incident on the microparticles PH having a high refractive index existing inside the composite particles, a part of the light may be totally reflected inside the microparticles PH to be totally reflected and sealed inside the microparticles PH. In contrast, as shown in FIG. 3B, when light is incident on the microparticles PL having a low refractive index existing inside the composite particles, the light is difficult to be enclosed inside the microparticles PL, and most of the light incident on the microparticles PL diffuses toward the light The transmission sheet 1 advances forward. As described above, in the composite particles 20, the resin adhesive 21 having a relatively high refractive index contains the first fine particles 22a having a relatively low refractive index, so the ratio of light enclosed in the fine particles 22 is reduced. As a result, the light diffusion and transmission sheet 1 has high brightness characteristics.

The refractive index of the resin adhesive 21 is preferably 1.44 or more, and more preferably 1.50 or more. The refractive index of the resin adhesive 21 is, for example, 1.55 or less. The refractive index of the first fine particles 22a is preferably 1.42 or less, and more preferably 1.38 or less. More preferably, the difference n _B -n _F from the refractive index n _{B of the} resin adhesive 21 minus the refractive index n _F of the first fine particles 22 a is 0.1 or more. Thereby, the refractive index difference between the resin adhesive 21 and the first fine particles 22a becomes large, and the light incident on the first fine particles 22a is easily diffused (scattered). Therefore, the light diffusion transmission sheet 1 has a higher brightness characteristic and a higher diffusion characteristic. The refractive index of the first fine particles 22a is, for example, 1.30 or more.

The resin adhesive 21 can contain fine particles 22 and has transparency to visible light. From the viewpoint of reducing the hardness of the composite particles 20 and reducing the possibility of damaging the members that come into contact with the light-diffusing transmission sheet 1, the resin adhesive 21 preferably contains a group selected from the group consisting of acrylic resin, polyurethane resin, and nylon. At least 1 kind of resin. Among them, it is preferable that the resin adhesive 21 is a polyurethane resin.

The first fine particles 22a are, for example, magnesium fluoride fine particles. The refractive index of magnesium fluoride is 1.38. Therefore, the magnesium fluoride fine particles have a preferable refractive index as the first fine particles 22a.

It is preferable that the average particle diameter of the composite particles 20 falls within a specific range so that the composite particles 20 can be uniformly dispersed in the base material resin 10. From this viewpoint, the average particle diameter of the composite particles 20 is, for example, 1 μm to 20 μm, more preferably 1 μm to 15 μm, and even more preferably 4 μm to 15 μm. This makes it possible to prevent spatial unevenness in the optical characteristics of the light diffusion and transmission sheet 1. In addition, it is possible to reduce the reflection loss of light caused by the light entering the space between the primary particles generated when the composite particles 20 aggregate. This makes it possible to improve the brightness characteristics of the light diffusion and transmission sheet 1. Furthermore, an interface where light is refracted in the light diffusion and transmission sheet 1 can be sufficiently secured. Thereby, the light-diffusion characteristic of the light-diffusion transmission sheet 1 can be improved. In addition, in this specification, "average particle diameter" means the D50 of the volume basis measured by the laser diffraction method. In addition, the "average particle diameter" can also be used as one of 50 or more particles that can be visually observed when a cross section of the light diffusion transmission sheet 1 or a cross section of the composite particle 20 is observed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The average value of the maximum diameter was calculated.

The shape of the composite particles 20 is preferably a granular shape having an aspect ratio of 1 to 2 from the viewpoint of imparting spatially uniform light diffusion characteristics to the light diffusion and transmission sheet 1. Here, the aspect ratio refers to the ratio (da / db) of the major axis da of the composite particles 20 to the minor axis db of the composite particles 20.

The average particle diameter of the first fine particles 22a is, for example, 10 nm to 10 μm. The average particle diameter of the first fine particles 22a is preferably 100 nm to 1 μm, and more preferably 100 nm to 300 nm. Thereby, the first fine particles 22a are easily dispersed uniformly in the composite particles 20, and the first fine particles 22a are appropriately contained in the resin adhesive 21.

The content rate of the composite particles 20 in the light diffusion transmission sheet 1 is, for example, 55% by mass or more, more preferably 60% by mass or more, and even more preferably 64% by mass or more. Thereby, the light-diffusion transmissive sheet 1 surely has a high brightness characteristic and a good light-diffusion characteristic. The content of the composite particles 20 in the light diffusion and transmission sheet 1 is, for example, 70% by mass or less, more preferably 68% by mass or less, and even more preferably 66% by mass or less. Thereby, the composite particles 20 are appropriately dispersed in the base material resin 10, and for example, the composite particles 20 can be prevented from being exposed on the surface of the light diffusion and transmission sheet 1.

The content of the fine particles 22 in the composite particles 20 is, for example, 30% to 99% by mass, more preferably 30% to 95% by mass, and even more preferably 50% to 90% by mass. The content of the resin binder 21 in the composite particles 20 is, for example, 1% to 70% by mass, more preferably 5% to 70% by mass, and even more preferably 10% to 50% by mass. Thereby, the light diffusion transmission sheet 1 has good light diffusion characteristics.

The content of the first fine particles 22a in the composite particles 20 is, for example, 1% to 26% by mass, more preferably 2% to 10% by mass, and even more preferably 4% to 9% by mass. Thereby, the light-diffusion transmissive sheet 1 more surely has a high luminance characteristic.

As shown in FIG. 2, the fine particles 22 may contain, for example, the second fine particles 22 b. In this case, the second fine particles 22b are, for example, selected from the group consisting of silica, polysiloxane, fluororesin, titanium dioxide, zinc oxide, zirconia, calcium carbonate, barium sulfate, zinc sulfide, aluminum hydroxide, glass, and At least one kind of fine particles in a group composed of an extender pigment. Thereby, it is possible to provide a light diffusion transmission sheet having higher brightness characteristics or a light diffusion transmission sheet having various optical characteristics.

The average particle diameter of the second fine particles 22b is, for example, 1 nm to 1 μm, more preferably 2 nm to 600 nm, and even more preferably 2 nm to 400 nm. Thereby, the second fine particles 22b are easily dispersed uniformly in the composite particles 20, and the second fine particles 22b are appropriately contained in the resin adhesive 21.

The fine particles 22 may contain fine particles of a different type from the first fine particles 22a like the second fine particles 22b. In this case, it is preferable that the composite particles 20 include only the fine particles having a lower refractive index than the resin binder 21 as the fine particles 22. Thereby, since light is not enclosed in the microparticles 22, the light-diffusion transmissive sheet 1 more surely has high brightness characteristics.

The composite particles 20 contain, as the fine particles 22, at least one fine particle selected from the group consisting of magnesium fluoride, silicon oxide, polysiloxane, and a fluororesin. Since magnesium fluoride, silicon oxide, polysiloxane, and fluororesin have relatively low refractive indices, the refractive index of the fine particles 22 of the composite particles 20 tends to become lower than the refractive index of the resin adhesive 21. Therefore, it is beneficial to improve the brightness characteristics of the light diffusion and transmission sheet 1.

The composite particles 20 contain, for example, only magnesium fluoride fine particles and silicon oxide fine particles as the fine particles 22. In this case, except that the refractive index of the fine particles 22 of the composite particles 20 tends to be lower than the refractive index of the resin binder 21, the composite particles 20 easily have the required mechanical strength.

As shown in FIG. 4, for example, the composite particles 20 may contain only the first fine particles 22 a as the fine particles 22. In this case, for example, the composite particle 20 contains only magnesium fluoride fine particles as the fine particles 22. As a result, the refractive index of the fine particles 22 of the composite particles 20 tends to be lower than the refractive index of the resin adhesive 21.

Next, an example of the manufacturing method of the light-diffusion transmission sheet 1 is demonstrated. A sol liquid is prepared in which the resin binder 21 and the fine particles 22 including at least the first fine particles 22a are dispersed. In the sol solution, the microparticles 22, a fluorescent dye, a fluorescent whitening agent, a dye, or a pigment different from the first microparticles 22a are dispersed as necessary. The composite particles 20 can be obtained by spray-drying using the prepared sol solution. By adjusting the solid content in the sol solution and the spraying conditions in spray drying, it is possible to suppress the aggregation of the primary particles and control the particle diameter of the composite particles 20 to an appropriate range.

Further, to the molten resin that becomes the resin binder 21, microparticles 22 containing at least the first microparticles 22a are added, and microparticles 22, fluorescent dyes, fluorescent brighteners, dyes, Or pigment and kneading, so that these additives are uniformly mixed with the molten resin. The composite particles 20 can also be obtained by pulverizing the pieces of the resin obtained in this way to a specific particle size. However, from the viewpoint of uniformly dispersing the fine particles 22 and the like in the resin binder 21 or efficiently producing the composite particles 20 having a preferable particle size and shape, it is more preferable to prepare the sol solution by spray drying. Manufacture composite particle 20.

The composite particles 20 prepared as described above are uniformly dispersed in a fluid containing the base material resin 10. In this manner, an ink containing the base material resin 10 and the composite particles 20 is prepared. By applying this ink to a substrate such as a PET film and curing the ink, the light-diffusing transmission sheet 1 can be obtained.

<Second Embodiment>

Next, a light diffusion transmission sheet 201 according to the second embodiment will be described. Since the silicon oxide composite particles described in Patent Document 1 are a two-component system of silicon oxide and titanium oxide, there is little room for adjusting the optical characteristics of the light diffusion and transmission sheet. For example, even if it is desired to adjust the content of silicon oxide and the content of titanium oxide in the silicon oxide composite particles to improve the brightness characteristics of the light diffusion transmission sheet, it may be difficult to sufficiently improve the brightness characteristics of the light diffusion transmission sheet. The light diffusion and transmission sheet may be used in a state where the light diffusion and transmission sheet is superposed with other members. In this case, it is important that the light-diffusing transmission sheet does not easily damage other members. According to Patent Documents 2 to 4, specific research on "composite particles that are not liable to damage other members" has not been conducted.

Based on this situation, a light diffusion transmission sheet has been developed with the aim of providing a light diffusion transmission sheet having composite particles that are conducive to improving the brightness characteristics of the light diffusion transmission sheet, and are not easy to damage other members overlapping the light diffusion transmission sheet. 201.

As shown in FIG. 5, the light diffusion and transmission sheet 201 of the present invention includes a base material resin 210 and composite particles 220. The composite particles 220 are dispersed in a base material resin 210. The base material resin 210 is not particularly limited, and is preferably a resin that has excellent dispersibility of the composite particles 220 and has transparency to visible light, weather resistance, moisture resistance, and heat resistance. Examples of the base material resin 210 include polyester polyols, linear polyesters, acrylic resins, amine resins, epoxy resins, melamine resins, silicone resins, amine ester resins, and vinyl acetate. Based resins, norbornene based resins, and polycarbonate resins. Various thermosetting resins and various ultraviolet curing resins can also be used. To these resins, an isocyanate-based hardening agent and various dispersants may be appropriately added. The light diffusion transmission sheet 201 may further include a substrate (not shown) such as a PET (polyethylene terephthalate) film, and the base material resin 210 in which the composite particles 220 are dispersed may be formed in a layered manner on the substrate.

As shown in FIG. 6, the composite particles 220 include a resin binder 221 and fine particles 222. The microparticles 222 are enclosed in a resin adhesive 221. The fine particles 222 include magnesium fluoride fine particles 222a as the first fine particles, and silicon oxide fine particles 222b. The content of the resin binder 221 in the composite particles 220 is 40% to 80% by mass, and the content of the microparticles 222 in the composite particles 220 is 20% to 60% by mass. Thus, the composite particles 220 are advantageous in that the brightness characteristics of the light diffusion transmission sheet 201 are improved and other members overlapping the light diffusion transmission sheet 201 are not easily damaged.

It is preferable that the average particle diameter of the composite particles 220 falls within a specific range so that the composite particles 220 can be uniformly dispersed in the base material resin 210. From this viewpoint, the average particle diameter of the composite particles 220 is, for example, 1 μm to 20 μm, more preferably 1 μm to 15 μm, and even more preferably 4 μm to 15 μm. Thereby, it is possible to prevent the spatial unevenness of the optical characteristics in the light diffusion and transmission sheet 201. In addition, it is possible to reduce the reflection loss of light caused by the light entering the space between the primary particles generated when the composite particles 220 are aggregated. This makes it possible to improve the brightness characteristics of the light diffusion and transmission sheet 201. Furthermore, an interface where light is refracted in the light diffusion and transmission sheet 201 can be sufficiently secured. Thereby, the light-diffusion characteristic of the light-diffusion transmission sheet 201 can be improved.

From the viewpoint of imparting spatially uniform light diffusion characteristics to the light diffusion and transmission sheet 201, the shape of the composite particles 220 is preferably a granular shape having an aspect ratio of 1 to 2. Here, the aspect ratio refers to a ratio (da / db) of the major axis da of the composite particles 220 to the minor axis db of the complex particles 220.

The average particle diameter of the magnesium fluoride fine particles 222a is, for example, 10 nm to 10 μm. The average particle diameter of the magnesium fluoride fine particles 222a is preferably 100 nm to 1 μm, and more preferably 100 nm to 300 nm. Thereby, the magnesium fluoride fine particles 222a are easily dispersed uniformly in the composite particles 220, and the magnesium fluoride fine particles 222a are appropriately contained in the resin adhesive 221. For manufacturing reasons, sharp portions may be formed on the surface of the magnesium fluoride fine particles 222a. That is, when this situation is facilitated, as long as the average particle diameter of the magnesium fluoride fine particles 222a is within the above range, the surface of the magnesium fluoride fine particles 222a in the composite particles 220 can be suppressed from being exposed. Therefore, the composite particles 220 are beneficial to other members that do not easily overlap the light diffusion and transmissive sheet 201.

The average particle diameter of the silicon oxide fine particles 222b is, for example, 1 nm to 1 μm, more preferably 2 nm to 600 nm, and even more preferably 2 nm to 400 nm. Thereby, the silicon oxide fine particles 222b are easily and uniformly dispersed in the composite particles 220, and the silicon oxide fine particles 222b are appropriately contained in the resin adhesive 221. The silicon oxide fine particles 222b have a spherical shape, for example.

Magnesium fluoride has a relatively low refractive index (1.38). Therefore, in most cases, the magnesium fluoride fine particles 222 a have a refractive index lower than that of the resin adhesive 221. Thereby, it is suppressed that the light incident on the magnesium fluoride microparticles 222a is totally reflected inside the magnesium fluoride microparticles 222a to be totally reflected and sealed inside the magnesium fluoride microparticles 222a. As a result, more light penetrates the light diffusion and transmission sheet 201, so the light diffusion and transmission sheet 201 has a high brightness characteristic.

The refractive index of silicon oxide is about 1.45. In this way, the fine particles 222 in the composite particles 220 include magnesium fluoride fine particles 222a and silicon oxide fine particles 222b having different refractive indexes. Therefore, by adjusting the content of the magnesium fluoride fine particles 222a in the composite particles 220 and the content of the silicon oxide fine particles 222b in the composite particles 220, the optical characteristics of the light diffusion transmission sheet 201 can be widely adjusted.

The composite particles 220 may further contain a group selected from the group consisting of silica, polysiloxane, fluororesin, titanium dioxide, zinc oxide, zirconia, calcium carbonate, barium sulfate, zinc sulfide, aluminum hydroxide, glass, and physical pigments. At least one kind of fine particles is used as the fine particles 222. Thereby, various optical characteristics and mechanical characteristics can be provided to the composite particle 220. In addition, the optical characteristics of the light diffusion and transmission sheet 201 can be adjusted in a wider range.

On the other hand, the composite particles 220 may contain only the magnesium fluoride fine particles 222 a and the silicon oxide fine particles 222 b as the fine particles 222. In this case, the light diffusion and transmission sheet 201 also has high brightness characteristics. In addition, it is possible to prevent adjustment of the content rate of the various fine particles 222 in the composite particles 220 from becoming too complicated.

The resin adhesive 221 may contain the fine particles 222 and has transparency to light (for example, visible light) in a specific wavelength region. From the viewpoint of improving the straightness of light in the light diffusion transmission sheet 201 and improving the brightness characteristics of the light diffusion transmission sheet 201, the refractive index n _{M of the} base resin 210 and the refractive index of the resin adhesive 221 are more preferable n _B of a difference | n _B -n _M | small. From this viewpoint, | n _B -n _M | is 0.1 or less. On the other hand, it is preferable that the resin adhesive 221 has a refractive index higher than that of magnesium fluoride, so as to reliably suppress light from being enclosed inside the magnesium fluoride fine particles 222a. The refractive index of the resin adhesive 221 is, for example, 1.50 to 1.55.

From the viewpoint of reducing the hardness of the composite particles 220 and reducing the possibility of damaging the members that come in contact with the light-diffusing transmission sheet 201, the resin adhesive 221 preferably contains a group selected from the group consisting of acrylic resin, polyurethane resin, and nylon At least 1 kind of resin. Among them, the resin adhesive 221 is preferably a polyurethane resin.

The content rate of the composite particles 20 in the light diffusion transmission sheet 201 is, for example, 55% by mass or more, more preferably 60% by mass or more, and even more preferably 64% by mass or more. Thereby, the light-diffusion transmissive sheet 201 surely has a high brightness characteristic and a good light-diffusion characteristic. The content of the composite particles 202 in the light diffusion and transmission sheet 201 is, for example, 70% by mass or less, more preferably 68% by mass or less, and even more preferably 66% by mass. Thereby, the composite particles 220 are appropriately dispersed in the base material resin 210, and for example, the composite particles 220 can be prevented from being exposed on the surface of the light diffusion and transmission sheet 201.

The content of the magnesium fluoride fine particles 222a in the composite particles 220 is, for example, 1% to 26% by mass, more preferably 2% to 10% by mass, and even more preferably 4% to 9% by mass. Thereby, the light-diffusion transmissive sheet 201 more surely has a high brightness characteristic.

The content of the silicon oxide fine particles 222b in the composite particles 220 is, for example, 1% to 59% by mass, more preferably 20% to 59% by mass, and even more preferably 20% to 49% by mass. Thereby, the light-diffusion transmissive sheet 201 more surely has a high brightness characteristic.

Next, an example of a method for manufacturing the light diffusion and transmission sheet 201 will be described. A sol was prepared in which a resin binder 221 and fine particles 222 containing at least magnesium fluoride fine particles 222a and silicon oxide fine particles 222b were dispersed. In the sol solution, if necessary, the fine particles 222, fluorescent dyes, fluorescent whitening agents, dyes, or pigments different from the magnesium fluoride fine particles 222a and the silicon oxide fine particles 222b are dispersed. The composite particles 220 can be obtained by spray-drying using the prepared sol solution. By adjusting the content of the solid components in the sol solution and the spraying conditions in spray drying, it is possible to suppress the aggregation of the primary particles and control the particle diameter of the composite particles 220 to an appropriate range.

In addition, to the molten resin serving as the resin adhesive 221, particles 222 containing at least magnesium fluoride particles 222a and silica particles 222b are added, and if necessary, particles 222 and magnesium oxide particles 222a and silica particles 222b of different types are added. A fluorescent dye, a fluorescent whitening agent, a dye, or a pigment is kneaded, and these additives are uniformly mixed in the molten resin. The composite particles 220 can also be obtained by pulverizing the pieces of the resin obtained in this way to a specific particle size. However, from the viewpoint of uniformly dispersing the fine particles 222 and the like in the resin adhesive 221 or efficiently producing the composite particles 220 having a preferable particle size and shape, it is more preferable to use sol solution preparation and spray drying. A composite particle 220 is produced.

The composite particles 220 prepared as described above are uniformly dispersed in a fluid containing the base material resin 210. In this manner, an ink containing the base material resin 210 and the composite particles 220 is prepared. By applying this ink to a substrate such as a PET film and curing the ink, a light-diffusing transmission sheet 201 can be obtained.

<Third Embodiment>

Next, a light diffusion transmission sheet 301 according to the third embodiment will be described. According to the techniques described in Patent Documents 1 and 2, the fine particles enclosed in the composite particles have a relatively high refractive index. In addition, according to the technique described in Patent Document 3, it has been suggested that the surface of fine particles having a relatively high refractive index is coated with a material having a relatively low refractive index. However, these technologies are not necessarily conducive to improving the brightness of a light-diffusing and transmissive sheet in which composite particles are dispersed. In addition, Patent Document 4 does not describe or suggest dispersing composite particles in a transparent substrate. The main purpose of the technique described in Patent Document 5 is to make the microparticles partially distributed in the shell, which is not necessarily conducive to improving the brightness of the light diffusion and transmission sheet.

According to the technology described in Patent Document 2, when the internal scattering particles are dispersed in the matrix resin, there is a possibility that the organic material of the internal scattering particles is eluted to an organic solvent for dissolving the matrix resin or dispersing the internal scattering particles. Sex. According to Patent Documents 1, 3 to 5, the specific elution of the resin component of the composite particles to an organic solvent has not been studied.

Based on this situation, a light diffusion transmission sheet 301 has been developed with the purpose of providing a light diffusion transmission sheet having composite properties that are advantageous for improving the brightness of the light diffusion transmission sheet and for suppressing the elution of the resin binder to organic particles.

As shown in FIG. 7, the light diffusion transmission sheet 301 of the present invention includes a base material resin 310 and composite particles 320 having a core-shell structure. The composite particles 320 are dispersed in a base material resin 310. The base material resin 310 is not particularly limited, and is preferably a resin that has excellent dispersibility of the composite particles 320 and has transparency to visible light, weather resistance, moisture resistance, and heat resistance. Examples of the base material resin 310 include polyester polyol, linear polyester, acrylic resin, amine resin, epoxy resin, melamine resin, silicone resin, amine ester resin, and vinyl acetate. Based resins, norbornene based resins, and polycarbonate resins. Various thermosetting resins and various ultraviolet curing resins can also be used. It is also possible to appropriately add an isocyanate-based hardener and various dispersants to these resins. The light diffusion transmission sheet 301 may further include a substrate (not shown) such as a PET (polyethylene terephthalate) film, and the base material resin 10 in which the composite particles 320 are dispersed may be formed on the substrate.

As shown in FIG. 8, the composite particle 320 includes a core 320 a and a shell 320 b. The core 320 a is formed of the first resin adhesive 321 and the core fine particles 322. The first resin adhesive 321 has a refractive index higher than 1.43. The core fine particles 322 are enclosed in a first resin adhesive 321. The core fine particles 322 include low refractive index fine particles 322a (corresponding to the first fine particles) having a refractive index of 1.43 or less. The outer shell 320b is formed by the second resin adhesive 323 and the outer shell fine particles 324 enclosed in the second resin adhesive 323. The casing 320b covers at least a part of the surface of the core 320a. The outer shell 320b preferably covers the entire surface of the core 320a. The composite particle 320 may include two or more cores 320a.

As shown in FIG. 9A, when light is incident on the microparticles PH having a high refractive index existing inside the core, a part of the light may be totally reflected inside the microparticles PH to be totally reflected and sealed inside the microparticles PH. In contrast, as shown in FIG. 9B, when light is incident on the microparticles PL having a low refractive index existing inside the core, the light is not easily enclosed in the microparticles PL, and most of the light incident on the microparticles PL diffuses toward the light. The transmission sheet 301 moves forward. As described above, in the core 320 a, the low-refractive index particles 322 a having a relatively low refractive index are enclosed in the first resin adhesive 321 having a relatively high refractive index, and therefore, the number of particles enclosed in the core particles 322 is reduced. Ratio of light. As a result, the light diffusion and transmission sheet 301 has high brightness characteristics.

In addition, since the composite particles 320 are provided with an outer shell 320b including outer shell fine particles 324, even when the composite particles 320 are in contact with an organic solvent during the manufacturing process of the light diffusion transmission sheet 301, it is difficult for the first resin adhesive 321 to elute to Organic solvents. In addition, the composite particles 320 are provided with a housing 320b in addition to the core 320a, thereby increasing the degree of freedom in adjusting the composition of the system. As a result, it is easy to improve the optical characteristics of the composite particles 320. For example, it is possible to favorably improve the brightness characteristic or the light diffusion characteristic (atomization rate) of the light diffusion transmission sheet 301.

The refractive index of the first resin adhesive 321 is preferably 1.44 or more, and more preferably 1.50 or more. The refractive index of the first resin adhesive 321 is, for example, 1.55 or less. The refractive index of the low refractive index fine particles 322a is preferably 1.42 or less, and more preferably 1.38 or less. It is more preferable that the difference n _B -n _F from the refractive index n _{B of the} first resin adhesive 321 minus the refractive index n _F of the low refractive index fine particles 322 a is 0.1 or more. Thereby, the refractive index difference between the first resin adhesive 321 and the low-refractive-index fine particles 322a becomes large, and light incident on the low-refractive-index fine particles 322a is easily diffused (scattered). Therefore, the light diffusion transmission sheet 301 has high brightness characteristics and good light diffusion characteristics. The refractive index of the low refractive index fine particles 322a is, for example, 1.30 or more.

The first resin adhesive 321 can contain core fine particles 322 and has transparency to visible light. From the viewpoint of reducing the hardness of the composite particles 320 and reducing the possibility of damaging the members that come in contact with the light diffusion transmission sheet 301, the first resin adhesive 321 is preferably selected from the group consisting of acrylic resin, polyurethane resin, and nylon. At least one resin in the group. Among them, it is preferable that the first resin adhesive 321 is a polyurethane resin.

The low refractive index fine particles 322a are, for example, magnesium fluoride fine particles. The refractive index of magnesium fluoride is 1.38. Therefore, the magnesium fluoride fine particles have a refractive index which is preferable as the low refractive index fine particles 322a.

It is desirable that the average particle diameter of the composite particles 320 falls within a specific range so that the composite particles 320 can be uniformly dispersed in the base material resin 310. From this viewpoint, the average particle diameter of the composite particles 320 is, for example, 1 μm to 20 μm, more preferably 1 μm to 15 μm, and even more preferably 4 μm to 15 μm. Thereby, it is possible to prevent the spatial unevenness of the optical characteristics in the light diffusion and transmission sheet 301. In addition, it is possible to reduce the reflection loss of light caused by the light entering the space between the primary particles generated when the composite particles 320 are aggregated. As a result, it is possible to improve the brightness characteristics of the light diffusion and transmission sheet 301. Furthermore, an interface where light is refracted in the light diffusion and transmission sheet 301 can be sufficiently secured. Thereby, the light-diffusion characteristic of the light-diffusion transmission sheet 301 can be improved.

From the viewpoint of imparting spatially uniform light diffusion characteristics to the light diffusion and transmission sheet 301, the shape of the composite particles 320 is preferably a granular shape having an aspect ratio of 1 to 2. Here, the aspect ratio refers to a ratio (da / db) of the major axis da of the composite particle 320 to the minor axis db of the complex particle 320.

The average particle diameter of the low refractive index fine particles 322a is, for example, 10 nm to 10 μm. The average particle diameter of the low-refractive-index fine particles 322a is preferably 100 nm to 1 μm, and more preferably 100 nm to 300 nm. Thereby, the low-refractive-index fine particles 322a are easily and uniformly dispersed in the core 320a, and the low-refractive-index fine particles 322a are appropriately contained in the first resin adhesive 321.

The content rate of the composite particles 320 in the light diffusion transmission sheet 301 is, for example, 55% by mass or more, more preferably 60% by mass or more, and even more preferably 64% by mass or more. Thereby, the light-diffusion transmissive sheet 301 surely has high brightness characteristics and good light-diffusion characteristics. The content of the composite particles 320 in the light diffusion and transmission sheet 301 is, for example, 70% by mass or less, more preferably 68% by mass or less, and even more preferably 66% by mass. Thereby, the composite particles 320 are appropriately dispersed in the base material resin 310, and for example, it is possible to suppress the composite particles 320 from being exposed on the surface of the light diffusion transmission sheet 301.

The ratio of the mass of the core 320 a in the composite particles 320 to the total mass of the composite particles 320 is, for example, 1% to 50%, more preferably 2% to 30%, and even more preferably 4% to 25%. On the other hand, the ratio of the mass of the outer shell 320b in the composite particles 320 to the total mass of the composite particles 320 is, for example, 50% to 99%, more preferably 70% to 98%, and even more preferably 75% to 96%. . Thereby, the elution of the first resin adhesive 321 to the organic solvent can be reliably suppressed, and a large amount of incident light can be introduced into the core 320a. As a result, the light-diffusion transmissive sheet 301 more surely has high brightness characteristics or good light-diffusion characteristics.

The content of the core fine particles 322 in the core 320a is, for example, 30% to 99% by mass, more preferably 30% to 95% by mass, and even more preferably 50% to 90% by mass. The content of the first resin binder 321 in the composite particles 320 is, for example, 1% to 70% by mass, more preferably 5% to 70% by mass, and even more preferably 10% to 50% by mass. Thereby, the light-diffusion transmissive sheet 301 more surely has a high brightness characteristic or a good light-diffusion characteristic.

The content of the low refractive index fine particles 322a in the core 320a is, for example, 1% to 26% by mass, more preferably 2% to 10% by mass, and even more preferably 4% to 9% by mass. Thereby, the light-diffusion transmissive sheet 301 more surely has high luminance characteristics.

As shown in FIG. 8, the core fine particles 322 may contain fine particles of a different type from the low refractive index fine particles 322 a. For example, the core fine particles 322 may further contain a component selected from the group consisting of silica, polysiloxane, fluororesin, titanium dioxide, zinc oxide, zirconia, calcium carbonate, barium sulfate, zinc sulfide, aluminum hydroxide, glass, and constitution pigment At least one microparticle in the group. Thereby, it is possible to provide a light diffusion transmission sheet 301 having higher brightness characteristics or a light diffusion transmission sheet 301 having various optical characteristics.

The average particle diameter of the microparticles other than the low refractive index microparticles 322a contained in the core microparticles 322 is, for example, 1 nm to 1 μm, more preferably 2 nm to 600 nm, and even more preferably 2 nm to 400 nm. Thereby, the microparticles other than the low-refractive-index microparticles 322a contained in the core microparticles 322 are easily and uniformly dispersed, and are appropriately contained in the first resin adhesive 321.

The core fine particles 322 preferably contain only fine particles having a refractive index lower than that of the first resin adhesive 321. Thereby, since the light is not enclosed in the core fine particles 322, the light diffusion and transmission sheet 301 more surely has a high brightness characteristic.

When the core fine particles 322 contain only particles having a refractive index lower than that of the first resin binder 321, for example, the core fine particles 322 contain a group selected from the group consisting of magnesium fluoride, silicon oxide, polysiloxane, and fluororesin. At least one kind of fine particles. Since the magnesium fluoride, silicon oxide, polysiloxane, and fluororesin have relatively low refractive indices, the refractive index of the core fine particles 322 is easily lower than that of the first resin adhesive 321. Therefore, the use of at least one kind of fine particles selected from the group consisting of magnesium fluoride, silicon oxide, polysiloxane, and fluororesin is advantageous for improving the brightness characteristics of the light diffusion transmission sheet 301.

The core fine particles 322 contain, for example, only magnesium fluoride fine particles and silicon oxide fine particles. In this case, the refractive index of the core fine particles 322 of the composite particles 320 is likely to be lower than the refractive index of the first resin adhesive 321, and in addition, the composite particles 320 are likely to have the required mechanical strength.

As shown in FIG. 10, the core fine particles 322 may include only the low refractive index fine particles 322 a. In this case, the core fine particles 322 contain, for example, only magnesium fluoride fine particles. Thereby, the light-diffusion transmissive sheet 301 has higher brightness characteristics more surely.

As the shell fine particles 324, various kinds of fine particles can be used from the viewpoint of imparting specific optical characteristics to the light diffusion transmission sheet 301 and appropriately suppressing the elution of the first resin adhesive 321 to an organic solvent. For example, the shell fine particles 324 contain a material selected from the group consisting of magnesium fluoride, silicon oxide, polysiloxane, fluororesin, titanium dioxide, zinc oxide, zirconia, calcium carbonate, barium sulfate, zinc sulfide, aluminum hydroxide, glass, and physical pigment At least one microparticle in the group.

The average particle diameter of the shell fine particles 324 is, for example, 1 nm to 10 μm, more preferably 2 nm to 2 μm, and even more preferably 2 nm to 1 μm. Thereby, the outer shell fine particles 324 are easily dispersed uniformly in the outer shell 320b, and the outer shell fine particles 324 are appropriately contained in the second resin adhesive 323.

The second resin adhesive 323 can contain the outer shell fine particles 324 and has transparency to visible light. From the viewpoint of reducing the hardness of the composite particles 320 and reducing the possibility of damaging the members that come in contact with the light diffusion transmission sheet 301, the second resin adhesive 323 is preferably selected from the group consisting of acrylic resin, polyurethane resin, and nylon. At least one resin in the group. Among them, it is preferable that the second resin adhesive 323 is a polyurethane resin.

The content of the shell fine particles 324 in the shell 320b is, for example, 1% to 99% by mass, more preferably 30% to 95% by mass, and even more preferably 75% to 90% by mass. The content of the second resin adhesive 323 in the housing 320b is, for example, 1% to 99% by mass, more preferably 5% to 70% by mass, and even more preferably 10% to 25% by mass. Thereby, the elution of the first resin adhesive 321 to the organic solvent is favorably suppressed. In addition, the hardness of the composite particles 320 is prevented from becoming too high. As a result, it is difficult for the light diffusion transmission sheet 301 to damage other members in contact with the light diffusion transmission sheet 301.

Next, an example of a manufacturing method of the light diffusion transmission sheet 301 will be described. A raw material in which the first resin binder 321 is dispersed, and a sol solution containing the core fine particles 322 of the low refractive index fine particles 322a are prepared. The sol liquid is prepared, for example, by mixing an emulsion containing a raw material of the first resin binder 321 and a colloid liquid containing low-refractive index particles 322a. Fluorescent dyes, fluorescent brighteners, dyes, or pigments can also be dispersed in the sol solution as needed. The core 320a can be obtained by performing spray drying using the prepared sol solution. By adjusting the solid content in the sol solution and the spraying conditions in spray drying, it is possible to suppress the aggregation of the primary particles and control the particle size of the core 320a to an appropriate range.

Alternatively, instead of performing spray drying, a specific cross-linking agent may be added to the sol solution and heated to cross-link the raw material of the first resin adhesive 321 to form the core 320a.

In addition, to the molten resin which is the raw material of the first resin binder 321, core fine particles 322 containing low refractive index fine particles 322a are added, and a fluorescent dye, fluorescent whitening agent, dye, or pigment is added and kneaded as necessary , So that these additives are uniformly mixed in the molten resin. The core 320a can also be obtained by pulverizing the pieces of the resin obtained in this way to a specific particle size. However, from the viewpoint of uniformly dispersing the core fine particles 322 in the first resin adhesive 321, or efficiently manufacturing the core 320a having a preferable particle size and shape, it is more preferable to use a sol solution preparation and The spray drying or the addition of a cross-linking agent makes the core 320a.

Next, a sol liquid in which the core 320a, the raw material of the second resin adhesive 323, and the shell fine particles 324 are dispersed is prepared. By using the prepared sol solution to perform spray drying, the composite particles 320 having a core-shell structure can be manufactured. By adjusting the content of solid components in the sol solution and the spraying conditions in spray drying, it is possible to produce composite particles 320 having a desired particle size and desired characteristics.

When a core 320a is formed by adding a specific cross-linking agent, a raw material in which the first resin binder 321 is dispersed and a core fine particle 322 containing low-refractive index fine particles 322a having a refractive index of 1.43 or less are prepared. A first sol solution is added to the first sol solution to crosslink the raw materials of the first resin adhesive 321 to crosslink the raw materials of the first resin adhesive 321 to form the core 320a. Under this premise, a second sol liquid in which the core 320a, the raw material of the second resin adhesive 323, and the shell fine particles 324 are dispersed is prepared, and the second sol liquid is spray-dried. In this case, the composite particles 320 can be produced by one spray drying.

The composite particles 320 prepared as described above are uniformly dispersed in a fluid containing the base material resin 310. In this manner, an ink containing the base material resin 310 and the composite particles 320 is prepared. By applying this ink to a substrate such as a PET film and curing the ink, a light-diffusing transmission sheet 301 can be obtained.

Examples

The present invention will be described in detail using examples. However, the present invention is not limited to the following examples. First, examples and comparative examples of the first embodiment will be described.

<Example>

4.9 parts by weight of water obtained by pulverizing magnesium fluoride (manufactured by Kanto Chemical Co., Ltd., refractive index: 1.38) with a wet bead mill (bead diameter: 2 mm) was obtained. Dispersion (magnesium fluoride concentration: 5.5% by mass), 18.1 parts by weight of colloidal liquid A of silicon oxide fine particles (manufactured by Nissan Chemical Industries, Ltd., average particle diameter of silicon oxide fine particles: 2 nm to 3 nm, refractive index of silicon oxide fine particles: About 1.45, trade name: Snowtex XS), 42.7 parts by weight of colloidal liquid B of silicon oxide fine particles (manufactured by Nippon Chemical Industry Co., Ltd., average particle diameter of silicon oxide fine particles: 7 nm to 10 nm, refractive index of silicon oxide fine particles: about 1.45, Trade name: Silicadole 30S), 30.9 parts by weight of polyurethane emulsion A (manufactured by Mitsui Chemicals, trade name: Takelac W-6020, refractive index of polyurethane: 1.50 ~ 1.55), and 3.4 parts by weight of polyurethane emulsion B (Mitsui Chemical Co., Ltd. Manufactured, trade name: Takelac WS-6021, refractive index of polyurethane: 1.50 ~ 1.55) to prepare a sol solution. The content of magnesium fluoride in the solid content of the sol solution was 1% by mass, and the content of the solid content of the polyurethane in the solid content of the sol solution was 38.1% by mass. In addition to changing the amount of the aqueous dispersion of the magnesium fluoride fine particles so that the content of magnesium fluoride in the solid content of the sol solution becomes 2% by mass, 4% by mass, 6% by mass, and 8% by mass, A plurality of sol solutions were prepared in the same manner.

For each of the various sols prepared as described above, a micro-mist spray dryer (manufactured by Fujisaki Electric Corporation, product name: MDL-050) was used to spray-dry to produce a plurality of composite particles having different magnesium fluoride content rates . The spray conditions of the sol were adjusted so that the average particle diameter of the composite particles fell within a range of 4 μm to 15 μm.

Each of the plurality of kinds of composite particles prepared as described above is dispersed in an acrylic resin to prepare a plurality of inks. Each of the plurality of inks was coated on a PET film having a thickness of 20 μm by a doctor blade method and cured, thereby preparing various samples. The thickness of the coating film in each sample was 7 to 15 μm, and the content of the composite particles in the coating film of each sample was 65% by mass.

<Comparative example>

8.8 parts by weight of an aqueous dispersion of glass fine particles (refractive index: 1.57, average particle size: 1 to 2 μm) (concentration of glass fine particles: 6% by mass) and 17.2 parts by weight of colloidal liquid A of silicon oxide fine particles (Nissan Chemical Manufactured by Industrial Co., Ltd., average particle diameter of silica fine particles: 2nm ~ 3nm, refractive index of silica fine particles: about 1.45, trade name: Snowtex XS), 40.8 parts by weight of colloidal liquid B of silica fine particles (manufactured by Japan Chemical Industry Corporation) , The average particle diameter of the silicon oxide fine particles: 7nm ~ 10nm, the refractive index of the silicon oxide fine particles: about 1.45, trade name: Siliconadole 30S), 29.9 parts by weight of polyurethane emulsion A (manufactured by Mitsui Chemicals, trade name: Takelac W-6020 , The refractive index of polyurethane: 1.50 ~ 1.55) and 3.3 parts by weight of polyurethane emulsion B (manufactured by Mitsui Chemicals, trade name: Takelac WS-6021, refractive index of polyurethane: 1.50 ~ 1.55) were mixed to prepare a sol solution. The content of glass fine particles in the solid content of the sol solution was 2% by mass, and the content of the solid content of the polyurethane in the solid content of the sol solution was 38.1% by mass. A variety of sol liquids were prepared such that the content of glass in the solid content of the sol liquid was changed to 4% by mass, 6% by mass, 8% by mass, and 10% by mass in order to change the amount of the aqueous dispersion of glass fine particles.

For each of the various sols prepared as described above, a micro-mist spray dryer (manufactured by Fujisaki Electric Corporation, product name: MDL-050) was used to spray-dry to produce a plurality of composite particles having different magnesium fluoride content rates . The spray conditions of the sol were adjusted so that the average particle diameter of the composite particles fell within a range of 4 μm to 15 μm. The average particle diameter of the composite particles was measured using a laser diffraction / scattering type particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., product name: Microtrac (MT-3000II)). A sample used in this measurement was prepared by mixing an appropriate amount of the dried composite particles with pure water and applying ultrasonic vibration (130 W for 1 minute) to disperse the composite particles in pure water.

Each of the plurality of types of composite particles produced as described above was dispersed in an acrylic resin to prepare a plurality of types of inks. Each of the plurality of inks was coated on a PET film having a thickness of 20 μm by a doctor blade method and cured, thereby preparing various samples. The thickness of the coating film in each sample was 7 to 15 μm, and the content of the composite particles in the coating film of each sample was 65% by mass.

<Measurement of brightness characteristics>

The brightness of each sample of the example and the sample of the comparative example was measured using a brightness measuring device (manufactured by HI-LAND, product name: RISA-COLOR ONE). The backlight device of the iPhone 5 made by Apple was used as the light source. Furthermore, "iPhone" is a registered trademark of Apple Inc. The measurement position of the brightness is located on the opposite side of the sample from the light source, and the distance between the measurement position of the brightness and the sample is 100 cm. The evaluation results of each sample are shown in FIG. 11. Further, in FIG. 11, when the relative value of the brightness is 100%, the value of the brightness is 10 ⁴ cd / cm ² .

As shown in FIG. 11, it is suggested that the sample of the example has higher brightness characteristics than the sample of the comparative example.

<Measurement of atomization rate>

Using a spectrophotometer (manufactured by Shimadzu Corporation, product name: UV-3600) and an integrating sphere, the haze ratio of each sample of the example and each sample of the comparative example to incident light with a wavelength of 555 nm was measured. The results are shown in FIG. 12. The samples of the examples showed a higher atomization rate than 91%.

Next, an example of the second embodiment will be described. First, the evaluation method of the samples of each Example and each comparative example is demonstrated.

<Evaluation of damage imparting characteristics>

Using the device shown in FIG. 13, the samples of the light diffusion transmission sheets of Examples 14 and 15 and the samples of the light diffusion transmission sheets of Comparative Examples 9 to 11 were evaluated to the extent that other members were damaged due to contact. A brightness enhancement film PS (manufactured by 3M Corporation, BEF4-GT-90 (24)) with a length of 100 mm and a width of 30 mm was attached to the support table 40 using a double-sided tape. Next, a sample Sa of a light diffusion transmissive sheet having a length of 20 mm and a width of 15 mm was attached to the planar friction element 31 using a double-sided tape. Furthermore, as shown in FIG. 13, the sample Sa is arrange | positioned so that the sample Sa may be in contact with the brightness enhancement film PS. At this time, a weight 32 is mounted on the upper surface of the planar friction element 31, and a load of 150 g is applied to the brightness enhancement film PS. In this state, the planar friction element 31 was caused to reciprocate 100 mm on the brightness enhancement film PS at an average speed of 8.7 m / min, and the brightness enhancement film PS was rubbed with the sample Sa. The damage of the brightness enhancement film PS after rubbing with the sample Sa was evaluated by visual inspection in three stages. The case where the brightness enhancement film PS is less damaged is evaluated as "0", the case where the brightness enhancement film PS is slightly damaged is evaluated as "1", and the case where the brightness enhancement film PS is more damaged is evaluated as "2". . The results are shown in Table 3.

<Measurement of brightness characteristics>

The brightness of the samples of Examples 1 to 13 and Comparative Examples 1 to 8 was measured using a brightness measuring device (manufactured by HI-LAND, product name: RISA-COLOR ONE). As a light source, a backlight device of the iPhone 5 manufactured by Apple was used. Furthermore, "iPhone" is a registered trademark of Apple Inc. The measurement position of the brightness is located on the opposite side of the sample from the light source, and the distance between the measurement position of the brightness and the sample is 100 cm. The evaluation results of each sample are shown in FIG. 14. Further, in FIG. 14, when the relative value of the brightness is 100%, the value of the brightness is 10 ⁴ cd / cm ² .

<Examples 1 to 15>

Polyurethane Emulsion A (manufactured by Mitsui Chemicals, trade name: Takelac W-6020, refractive index of Polyurethane: 1.50 ~ 1.55), and polyurethane emulsion B (manufactured by Mitsui Chemicals, trade name :) are shown in Tables 1 and 3. Takelac WS-6021, aqueous dispersion of polyurethane (refractive index: 1.50 ~ 1.55), magnesium fluoride particles (manufactured by Kanto Chemical Co., Ltd., average particle diameter (D50): 0.25 μm, refractive index: 1.38) (magnesium fluoride concentration: 6% by mass), colloidal liquid A of silicon oxide fine particles (manufactured by Nissan Chemical Industries, Ltd., average particle diameter of silicon oxide fine particles: 2nm to 3nm, refractive index of silicon oxide fine particles: about 1.45, trade name: Snowtex XS), and oxidation Colloidal liquid B of silicon fine particles (manufactured by Nippon Chemical Industry Co., Ltd., average particle diameter of silicon oxide fine particles: 7 nm to 10 nm, refractive index of silicon oxide fine particles: about 1.45, trade name: Silicole 30S) were mixed to prepare Examples 1 to 15 Of sol liquid. The sol solution of Example 1 and the sol solution of Example 2 were prepared in the same batch. The sol solution of Example 3 and the sol solution of Example 4 were prepared in the same batch. The sol solutions of Examples 5 to 8 were prepared in the same batch. The sol solution of Example 9 and the sol solution of Example 10 were prepared in the same batch. The sol liquids of Examples 11 to 13 were prepared in the same batch. Furthermore, the magnesium fluoride fine particles are produced by pulverizing a block of magnesium fluoride, and there are sharp portions on the surface of the magnesium fluoride fine particles.

For each of the sols prepared in Examples 1 to 15 prepared as described above, a micro-mist spray dryer (made by Fujisaki Electric Corporation, product name: MDL-050) was used to spray-dry, thereby preparing Examples 1 to 15 Composite particles. The composite particles of Example 1 and the composite particles of Example 2 were produced by spray drying in the same batch. The composite particles of Example 3 and the composite particles of Example 4 were produced by spray drying in the same batch. The composite particles of Examples 5 to 8 were prepared by spray drying in the same batch. The composite particles of Example 9 and the composite particles of Example 10 were produced by spray drying in the same batch. The composite particles of Examples 11 to 13 were prepared by spray drying in the same batch. The spraying conditions of the sol liquid were adjusted so that the average particle diameter of the composite particles of each example fell within a range of 4 μm to 15 μm. The average particle diameter of the composite particles in each example was measured using a laser diffraction / scattering particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., product name: Microtrac (MT-3000II)). The sample used in this measurement was prepared by mixing an appropriate amount of the dried composite particles of each example in pure water, and applying ultrasonic vibration (130 W for 1 minute) to disperse the composite particles in pure water.

Each of the composite particles of Examples 1 to 15 prepared as described above was dispersed in an acrylic resin to prepare the inks of Examples 1 to 15. The ink of Example 1 and the ink of Example 2 were prepared in the same batch. The ink of Example 3 and the ink of Example 4 were prepared in the same batch. The ink of Example 5 and the ink of Example 6 were prepared in the same batch. The ink of Example 7 and the ink of Example 8 were prepared in the same batch. The ink of Example 9 and the ink of Example 10 were prepared in the same batch. The ink of Example 11 and the ink of Example 12 were prepared in the same batch. Each of the inks of Examples 1 to 15 was applied to a PET film having a thickness of 20 μm by a doctor blade method and cured, thereby preparing samples of Examples 1 to 15. The sample of Example 1 and the sample of Example 2 were made in the same batch. The sample of Example 3 and the sample of Example 4 were made in the same batch. The sample of Example 5 and the sample of Example 6 were made in the same batch. The sample of Example 7 and the sample of Example 8 were made in the same batch. The sample of Example 9 and the sample of Example 10 were made in the same batch. The sample of Example 11 and the sample of Example 12 were made in the same batch. The thickness of the coating film in each sample was 7 to 15 μm, and the content of the composite particles in the coating film of each sample was 65% by mass.

<Comparative Examples 1 to 11>

Comparative Example 1 was prepared by mixing polyurethane emulsion A, polyurethane emulsion B, aqueous dispersion of magnesium fluoride microparticles, colloidal liquid A of silicon oxide microparticles, and colloidal liquid B of silicon oxide microparticles in the amounts shown in Tables 2 and 3. ~ 11 sol solution. The sol solution of Comparative Example 1 and the sol solution of Comparative Example 2 were prepared in the same batch. The sol solution of Comparative Example 3 and the sol solution of Comparative Example 4 were prepared in the same batch. The sol solution of Comparative Example 5 and the sol solution of Comparative Example 6 were prepared in the same batch. The sol solution of Comparative Example 7 and the sol solution of Comparative Example 8 were prepared in the same batch. In addition, in Comparative Example 1, Comparative Example 2, and Comparative Example 9, a sol liquid was prepared without adding a polyurethane emulsion.

Each of the sols of Comparative Examples 1 to 11 prepared as described above was spray-dried using a micro-mist spray dryer (manufactured by Fujisaki Electric Corporation, product name: MDL-050) to prepare Comparative Examples 1 to 11 Composite particles. The composite particles of Comparative Example 1 and the composite particles of Comparative Example 2 were produced by spray drying in the same batch. The composite particles of Comparative Example 3 and the composite particles of Comparative Example 4 were produced by spray drying in the same batch. The composite particles of Comparative Example 5 and the composite particles of Comparative Example 6 were produced by spray drying in the same batch. The composite particles of Comparative Example 7 and the composite particles of Comparative Example 8 were produced by spray drying in the same batch. The spray conditions of the sol liquid were adjusted so that the average particle diameter of the composite particles of each comparative example fell within a range of 4 μm to 15 μm. The average particle diameter of the composite particles in each comparative example was measured in the same manner as in the examples.

Each of the composite particles of Comparative Examples 1 to 11 prepared as described above was dispersed in an acrylic resin to prepare inks of Comparative Examples 1 to 11. The ink of Comparative Example 1 and the ink of Comparative Example 2 were prepared in the same batch. The ink of Comparative Example 3 and the ink of Comparative Example 4 were prepared in the same batch. The ink of Comparative Example 5 and the ink of Comparative Example 6 were prepared in the same batch. The ink of Comparative Example 7 and the ink of Comparative Example 8 were prepared in the same batch. Each of the inks of Comparative Examples 1 to 11 was applied to a PET film having a thickness of 20 μm by a doctor blade method and cured, thereby preparing samples of Comparative Examples 1 to 11. The sample of Comparative Example 1 and the sample of Comparative Example 2 were made in the same batch. The sample of Comparative Example 3 and the sample of Comparative Example 4 were made in the same batch. The sample of Comparative Example 5 and the sample of Comparative Example 6 were made in the same batch. The sample of Comparative Example 7 and the sample of Comparative Example 8 were produced in the same batch. The thickness of the coating film in each sample was 7 to 15 μm, and the content of the composite particles in the coating film of each sample was 65% by mass.

As shown in FIG. 14, the samples of Examples 1 to 13 have relatively high brightness characteristics. Therefore, it was suggested that the composite particles having a polyurethane content of 40% to 80% by mass as a resin binder are beneficial for improving the brightness characteristics of the light diffusion and transmission sheet. In addition, as shown in Table 3, it is suggested that the samples of Examples 14 and 15 are less likely to damage other members than the samples of Comparative Examples 9 to 11.

Next, an example of the third embodiment will be described. First, the evaluation methods of the samples of the respective examples and comparative examples will be described.

<Measurement of brightness characteristics and chromaticity>

The brightness characteristics and chromaticity of each sample of each example and the sample of the comparative example were measured using a brightness measuring device (manufactured by HI-LAND, product name: RISA-COLOR ONE). As a light source, a backlight device of the iPhone 5 manufactured by Apple was used. Furthermore, "iPhone" is a registered trademark of Apple Inc. The measurement position of brightness and chromaticity is located on the opposite side of the sample from the light source, and the distance between the measurement position of brightness and chromaticity and the sample is 100 cm. The evaluation results of each sample are shown in Table 4. In Table 4, when the relative value of the brightness is 100%, the value of the brightness is 10 ⁴ cd / cm ² .

<Measurement of atomization rate>

A spectrophotometer (manufactured by Shimadzu Corporation, product name: UV-3600) and an integrating sphere were used to measure the atomization rate of the sample of each example and the sample of the comparative example with respect to incident light having a wavelength of 555 nm. The results are shown in Table 4.

<Dissolution characteristics to organic solvents>

The composite particles of Examples and Comparative Examples were dispersed in methyl ethyl ketone so that the concentration of the composite particles became 9% by mass. The dispersion liquid of each composite particle was heated at 80 ° C for 2 hours. Then, the supernatant of the dispersion was taken, and the supernatant was dried to calculate the concentration of the solid component contained in the supernatant. The concentration of the solid components contained in the supernatant was defined as the dissolution rate. The results are shown in Table 4.

<Example 1-A>

29.8 parts by weight of water obtained by pulverizing magnesium fluoride (manufactured by Kanto Chemical Co., Ltd., refractive index: 1.38) with a wet bead mill (bead diameter: 2 mm) was used to obtain the obtained magnesium fluoride fine particles (average particle size: 0.25 μm). Dispersion (magnesium fluoride concentration: 6% by mass), 10.1 parts by weight of colloidal liquid A of silicon oxide fine particles (manufactured by Nissan Chemical Industries, Ltd., average particle diameter of silicon oxide fine particles: 2nm to 3nm, refractive index of silicon oxide fine particles: About 1.45, trade name: Snowtex XS), 23.8 parts by weight of colloidal liquid B of silicon oxide microparticles (manufactured by Nippon Chemical Industry Co., Ltd., average particle diameter of silicon oxide microparticles: 7 nm to 10 nm, refractive index of silicon oxide micro particles: about 1.45, Trade name: Silicadole 30S), 32.7 parts by weight of polyurethane emulsion A (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takelac W-6020, refractive index of polyurethane: 1.50 ~ 1.55), and 3.6 parts by weight of polyurethane emulsion B (Mitsui Chemical Co., Ltd. Manufacture, trade name: Takelac WS-6021, refractive index of polyurethane: 1.50 ~ 1.55) and mixed to prepare sol liquid A. The solid content of magnesium fluoride in the solid content of the sol solution A was 8% by mass, the solid content of the polyurethane in the solid content of the sol solution A was 50% by mass, and the content of the sol solution A was 50% by mass. The content of the silica fine particles in the solid component was 42% by mass.

The sol liquid A prepared in the above manner was spray-dried using a micro-mist spray dryer (manufactured by Fujisaki Electric Corporation, product name: MDL-050) to prepare the core of Example 1-A. The average particle diameter of the core of Example 1-A was 4 to 15 μm. The average particle diameter of the core of Example 1-A was measured using a laser diffraction / scattering particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., product name: Microtrac MT-3000II). The sample used in this measurement was prepared by mixing an appropriate amount of the dried core of Example 1-A with pure water and applying ultrasonic vibration (130 W for 1 minute) to disperse the core in pure water.

Next, 6.5 parts by weight of the powdery core of Example 1-A and 21.4 parts by weight of colloidal liquid A of silicon oxide fine particles (manufactured by Nissan Chemical Industries, Ltd., average particle diameter of silicon oxide fine particles: 2 nm to 3 nm, oxidized Refractive index of silicon fine particles: about 1.45, trade name: Snowtex XS), 50.5 parts by weight of colloidal liquid B of silicon oxide fine particles (manufactured by Japan Chemical Industry Co., Ltd., average particle diameter of silicon oxide fine particles: 7nm ~ 10nm, Refractive index: about 1.45, trade name: Silicadole 30S), 8.7 parts by weight of polyurethane emulsion A (manufactured by Mitsui Chemicals, trade name: Takelac W-6020, refractive index of polyurethane: 1.50 ~ 1.55), and 13.0 parts by weight of polyurethane Emulsion B (manufactured by Mitsui Chemicals, trade name: Takelac WS-6021, refractive index of polyurethane: 1.50 to 1.55) was mixed to prepare sol B. The content of the core in the solid content of the sol solution B is 20% by mass, and the content of the solid content of the polyurethane in the solid content of the sol solution B is 20% by mass. The content of the silica fine particles in the solid content of the sol solution B was 60% by mass.

The sol liquid B prepared in the above manner was spray-dried using a micro-mist spray dryer (manufactured by Fujisaki Electric Corporation, product name: MDL-050) to prepare the composite particles of Example 1-A. The average particle diameter of the composite particles of Example 1-A was 4 to 15 μm. The average particle diameter of the composite particles in Example 1-A was measured using a laser diffraction / scattering particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., product name: Microtrac MT-3000II). The sample used in this measurement was prepared by mixing an appropriate amount of the dried composite particles of Example 1-A in pure water, and applying ultrasonic vibration (130 W for 1 minute) to disperse the composite particles in pure water.

The composite particles of Example 1-A prepared as described above were dispersed in an acrylic resin to prepare the ink of Example 1-A. The ink of Example 1-A was applied to a PET film having a thickness of 20 μm by a doctor blade method and cured, thereby preparing a sample of Example 1-A. The thickness of the coating film in the sample was 7 to 15 μm, and the content of the composite particles in the coating film of the sample was 65% by mass.

<Example 2-A>

The content of the core in the solid content of the sol B, the content of the solid content of the polyurethane in the solid content of the sol B, and the content of the silica fine particles in the solid content of the sol B A composite particle of Example 2-A was prepared in the same manner as in Example 1-A, except that a sol solution B containing a core was prepared so as to be 10% by mass, 20% by mass, and 70% by mass. The average particle diameter of the composite particles of Example 2-A was 4 to 15 μm. A sample of Example 2-A was prepared in the same manner as in Example 1-A, except that the composite particle of Example 2-A was used instead of the composite particle of Example 1-A. The thickness of the coating film of the sample of Example 2-A was 7 to 15 μm, and the content of the composite particles in the coating film of the sample of Example 2-A was 65% by mass.

<Example 3-A>

Sol liquid A was prepared in the same manner as in Example 1-A. Next, 5.2 parts by weight of a crosslinking agent (manufactured by Nisshinbo Chemical Co., Ltd., product name: Carbodilite E-05) was added to the sol solution A, and the polyurethane was crosslinked by heating at 80 ° C for 4 hours. In this way, the core of Example 3-A was produced. The core of Example 3-A, 15.6 parts by weight of colloidal liquid A of silicon oxide microparticles (manufactured by Nissan Chemical Industries, Ltd., average particle diameter of silicon oxide microparticles: 2 nm to 3 nm, refractive index of silicon oxide micro particles: about 1.45 Trade name: Snowtex XS), 37.0 parts by weight of colloidal liquid B of silicon oxide fine particles (manufactured by Nippon Chemical Industry Co., Ltd., average particle diameter of the silicon oxide fine particles: 7 nm to 10 nm, refractive index of the silicon oxide fine particles: about 1.45, trade name: Silicadole 30S), 8.0 parts by weight of polyurethane emulsion A (manufactured by Mitsui Chemicals, trade name: Takelac W-6020, refractive index of polyurethane: 1.50 ~ 1.55), and 11.9 parts by weight of polyurethane emulsion B (manufactured by Mitsui Chemicals, Inc.) Name: Takelac WS-6021, refractive index of polyurethane: 1.50 ~ 1.55) was mixed to prepare sol liquid C. The solid content of the core in the solid content of the sol solution C is 10% by mass, the solid content of the polyurethane in the solid content of the sol solution C is 20% by mass, and the solid content of the sol C The content of the silicon oxide fine particles in the material component was 70% by mass.

A composite particle of Example 3-A was prepared in the same manner as in Example 1-A, except that the sol solution C was used instead of the sol solution B for spray drying. The average particle diameter of the composite particles in Example 3-A was 4 to 15 μm. In addition, except that the composite particles of Example 3-A were used instead of the composite particles of Example 1-A, a sample of Example 3-A was prepared in the same manner as in Example 1-A. The thickness of the coating film of the sample of Example 3-A was 7 to 15 μm, and the content of the composite particles in the coating film of the sample of Example 3-A was 65% by mass.

<Comparative Example 1-A>

Sol liquid A was prepared in the same manner as in Example 1-A. The sol solution A was spray-dried using a micro-mist spray dryer (manufactured by Fujisaki Electric Corporation, product name: MDL-050) to prepare composite particles of Comparative Example 1-A. The average particle diameter of the composite particles of Comparative Example 1-A was 4 to 15 μm. A sample of Comparative Example 1-A was prepared in the same manner as in Example 1-A, except that the composite particles of Comparative Example 1-A were used instead of the composite particles of Example 1-A. The thickness of the coating film of the sample of Comparative Example 1-A was 7 to 15 μm, and the content of the composite particles in the coating film of the sample of Comparative Example 1-A was 65% by mass.

As shown in Table 4, it is suggested that the samples of each example have higher brightness characteristics. In addition, it is suggested that the haze rate related to the samples of each example is higher than the haze rate related to the sample of Comparative Example 1-A, and the samples of each example have good light diffusion characteristics. In addition, it is suggested that the dissolution rate of the composite particles of each example is very low compared to the dissolution rate of the composite particles of Comparative Example 1-A. Even if the composite particles of each example are in contact with an organic solvent, the resin adhesive is not easily eluted to organic Solvent.

Claims (31)

    A light diffusion transmission sheet comprising: a base material resin; and composite particles containing a resin binder having a refractive index higher than 1.43, and fine particles enclosed in the resin binder, and the composite particles are dispersed in the base material. Material resin; the fine particles include first fine particles having a refractive index of 1.43 or less.         For example, the light-diffusion and transmissive sheet according to item 1 of the patent application range, wherein the average particle diameter of the composite particles is 1 μm to 20 μm.         For example, the light diffusing and transmissive sheet according to item 1 or 2 of the scope of patent application, wherein the average particle diameter of the first fine particles is 10 nm to 10 μm.         For example, the light-diffusion transmission sheet according to any one of claims 1 to 3, wherein the content of the fine particles in the composite particles is 30% to 99% by mass, and the content of the resin binder in the composite particles is The content rate is 1 to 70% by mass.         For example, the light-diffusion and transmissive sheet according to any one of claims 1 to 4, wherein the first fine particles are magnesium fluoride fine particles.         For example, the light-diffusion and transmissive sheet according to any one of claims 1 to 5, wherein the fine particles contain second fine particles, and the second fine particles are selected from the group consisting of silica, polysiloxane, fluororesin, titanium dioxide, At least one kind of fine particles in the group consisting of zinc oxide, zirconia, calcium carbonate, barium sulfate, zinc sulfide, aluminum hydroxide, glass, and constitution pigment.         For example, the light-diffusion and transmissive sheet according to any one of claims 1 to 6, wherein the composite particles contain only particles having a refractive index lower than the refractive index of the resin binder as the particles.         For example, the light-diffusion and transmissive sheet according to item 7 of the application, wherein the composite particles contain at least one kind of fine particles selected from the group consisting of magnesium fluoride, silicon oxide, polysiloxane, and fluororesin as the fine particles.         For example, the light-diffusion transmissive sheet according to item 7 of the patent application scope, wherein the composite particles contain only magnesium fluoride particles and silicon oxide particles as the particles.         For example, the light-diffusion and transmissive sheet according to item 7 of the patent application scope, wherein the composite particles contain only magnesium fluoride fine particles as the fine particles.         For example, the light-diffusion transmissive sheet according to any one of claims 1 to 10, wherein the resin adhesive includes at least one resin selected from the group consisting of acrylic resin, polyurethane resin, and nylon.         For example, the light-diffusing and transmissive sheet according to item 1 or 2 of the patent application scope, wherein the fine particles include the magnesium fluoride fine particles and the silicon oxide fine particles as the first fine particles, and the content of the resin binder in the composite particles is 40. The mass ratio is from 80% by mass to 80% by mass, and the content of the fine particles in the composite particles is from 20% by mass to 60% by mass.         For example, the light-diffusion transmission sheet according to item 12 of the application, wherein the average particle diameter of the above-mentioned magnesium fluoride fine particles is 10 nm to 10 μm.         For example, the light-diffusion and transmissive sheet according to item 12 or 13 of the application scope, wherein the average particle diameter of the silicon oxide fine particles is 1 nm to 1 μm.         For example, the light-diffusing and transmissive sheet according to any one of claims 12 to 14, wherein the composite particles further contain a material selected from the group consisting of silicon oxide, polysiloxane, fluororesin, titanium dioxide, zinc oxide, zirconia, calcium carbonate, and sulfuric acid. At least one kind of fine particles in a group consisting of barium, zinc sulfide, aluminum hydroxide, glass, and extender pigment is used as the fine particles.         For example, the light-diffusion and transmissive sheet according to any one of claims 12 to 14, wherein the composite particles contain only magnesium fluoride particles and silicon oxide particles as the particles.         For example, the light diffusing and transmissive sheet according to any one of claims 12 to 16, wherein the resin adhesive contains at least one resin selected from the group consisting of polyurethane resin, acrylic resin, and nylon.         For example, the light diffusing and transmissive sheet according to item 17 of the application, wherein the resin adhesive is a polyurethane resin.         For example, the light-diffusing and transmissive sheet according to item 1 or 2 of the patent application scope, wherein the composite particles are provided with a core, which is composed of the above-mentioned resin adhesive having a refractive index higher than 1.43, that is, the first resin adhesive, and an inner package. The first resin adhesive is formed of core particles containing the low-refractive index particles having a refractive index of 1.43 or less as the first particles; and a shell made of a second resin adhesive and enclosed in the above. The second resin adhesive is formed by shell fine particles, and the shell covers at least a part of the surface of the core.         For example, the light diffusing and transmissive sheet according to item 19 of the patent application range, wherein the average particle diameter of the low refractive index fine particles is 10 nm to 10 μm.         For example, the light-diffusing transmission sheet according to item 19 or 20 of the patent application scope, wherein the content of the core fine particles in the core is 30% to 99% by mass, and the first resin adhesive in the core is Its content is 1% to 70% by mass.         For example, the light-diffusing and transmissive sheet according to any one of claims 19 to 21, wherein the low-refractive index particles are magnesium fluoride particles.         For example, the light-diffusing and transmissive sheet according to any one of claims 19 to 22, wherein the core fine particles further contain a material selected from the group consisting of silicon oxide, polysiloxane, fluororesin, titanium dioxide, zinc oxide, zirconia, calcium carbonate, At least one fine particle in a group consisting of barium sulfate, zinc sulfide, aluminum hydroxide, glass, and extender pigment.         For example, the light-diffusion and transmissive sheet according to any one of claims 19 to 23, wherein the core fine particles only include fine particles having a refractive index lower than that of the first resin adhesive.         For example, the light diffusing and transmissive sheet according to item 24 of the patent application, wherein the core fine particles contain at least one fine particle selected from the group consisting of magnesium fluoride, silicon oxide, polysiloxane, and fluororesin.         For example, the light diffusing and transmissive sheet according to item 24 of the application, wherein the core fine particles only include magnesium fluoride fine particles and silicon oxide fine particles.         For example, the light-diffusion transmissive sheet according to item 24 of the patent application, wherein the core fine particles contain only magnesium fluoride fine particles.         For example, the light diffusing and transmissive sheet according to any one of claims 19 to 27, wherein the first resin adhesive includes at least one resin selected from the group consisting of acrylic resin, polyurethane resin, and nylon.         For example, the light-diffusing and transmissive sheet according to any one of claims 19 to 28, wherein the shell fine particles contain a material selected from the group consisting of magnesium fluoride, silicon oxide, polysiloxane, fluororesin, titanium dioxide, zinc oxide, zirconia, and carbonic acid. At least one kind of fine particles in a group consisting of calcium, barium sulfate, zinc sulfide, aluminum hydroxide, glass, and extender pigment.         For example, the light-diffusing and transmissive sheet according to any one of claims 19 to 29, wherein the second resin adhesive includes at least one resin selected from the group consisting of acrylic resin, polyurethane resin, and nylon.         A method, which is a method for manufacturing composite particles with a core-shell structure, and is a method for preparing a first sol liquid having a first resin binder having a refractive index higher than 1.43 dispersed therein Raw materials and core fine particles, the core fine particles containing low refractive index fine particles having a refractive index of 1.43 or less, adding a crosslinking agent to the first sol to crosslink the raw materials of the first resin adhesive, The raw material of the first resin adhesive is crosslinked to form a core, and a second sol liquid is prepared. The second sol liquid is dispersed with the core, the raw material of the second resin adhesive, and shell fine particles, and the second sol is dispersed. Liquid spray-dried.