Optical body with diffusion reflectivity, wall member, fitting, and solar shading device

1. An optical body with diffusion reflectivity comprising:

a first optical layer having a random concave-convex surface;

a reflecting layer formed on the concave-convex surface; and

a second optical layer formed on the reflecting layer so as to fill the concave-convex surface;

wherein the reflecting layer is a wavelength-selective reflecting layer for diffusely reflecting, of incident light, light in a specific wavelength band and transmitting light other than the specific wavelength band therethrough, and

wherein a value of transmission image clarity for the light at wavelengths transmitting through the optical body is not smaller than 50 when measured in conformity with JIS K-7105 using an optical comb with a comb width of 0.5 mm.

2. The optical body with diffusion reflectivity according to claim 1 , wherein a total value of transmission image clarity for the light at wavelengths transmitting through the optical body is not smaller than 230 when measured in conformity with JIS K-7105 using optical combs with comb widths of 0.125 mm, 0.5 mm, 1.0 mm and 2.0 mm.

3. The optical body with diffusion reflectivity according to claim 1 , wherein a difference in refractive index between the first optical layer and the second optical layer is not more than 0.010.

4. The optical body with diffusion reflectivity according to claim 1 , wherein the first optical layer and the second optical layer are made of a same resin having transparency in a visible range, and the second optical layer contains one or more additives.

5. The optical body with diffusion reflectivity according to claim 1 , wherein at least one of the first optical layer and the second optical layer absorbs light in a specific wavelength band within a visible range.

6. The optical body with diffusion reflectivity according to claim 1 , wherein an optical layer is formed by the first optical layer and the second optical layer, and

the optical body further comprises a light scatterer in at least one of positions on a surface of the optical layer, inside the optical layer, and between the wavelength-selective reflecting layer and the optical layer.

7. The optical body with diffusion reflectivity according to claim 1 , further comprising a water-repellent or hydrophilic layer on an incident surface of the optical body.

8. The optical body with diffusion reflectivity according to claim 1 , wherein the optical body diffusely reflects the light in the specific wavelength band to prevent the light in the specific wavelength band from entering a predetermined space, while transmitting the light other than the specific wavelength band therethrough to be taken into the predetermined space.

9. The optical body with diffusion reflectivity according to claim 1 , wherein the wavelength-selective reflecting layer is made of a transparent electroconductive film containing, as a main component, an electroconductive material having transparency in a visible range, or a functional film containing, as a main component, a chromic material that reversibly changes reflective performance thereof upon application of an external stimulus.

10. A window member including the optical body with diffusion reflectivity according to claim 1 .

11. A fitting including a lighting portion provided with the optical body with diffusion reflectivity according to claim 1 .

12. A solar shading device comprising one or plural solar shading members to cut off sunlight,

wherein the solar shading member includes the optical body with diffusion reflectivity according to claim 1 .

13. An optical body with diffusion reflectivity comprising:

a first optical layer having a random concave-convex surface;

a reflecting layer formed on the concave-convex surface; and

a second optical layer formed on the reflecting layer so as to fill the concave-convex surface;

wherein the reflecting layer is a semi-transmissive layer for diffusely reflecting part of incident light and transmitting the remaining light therethrough, and

wherein a value of transmission image clarity for the light at wavelengths transmitting through the optical body is not smaller than 50 when measured in conformity with JIS K-7105 using an optical comb with a comb width of 0.5 mm.

14. The optical body with diffusion reflectivity according to claim 2 , wherein the semi-transmissive layer has transmittance of 5% or more and 70% or less in a wavelength range of 500 nm or longer to 1000 nm or shorter.

15. A method for manufacturing an optical body with diffusion reflectivity, comprising:

forming a first optical layer having a random concave-convex surface;

forming a reflecting layer on the concave-convex surface; and

forming a second optical layer on the reflecting layer so as to fill the concave-convex surface;

wherein the reflecting layer is a wavelength-selective reflecting layer for diffusely reflecting light in a specific wavelength band and transmitting light other than the specific wavelength band therethrough, and

wherein a value of transmission image clarity for the light at wavelengths transmitting through the optical body is not smaller than 50 when measured in conformity with JIS K-7105 using an optical comb with a comb width of 0.5 mm.

16. The method for manufacturing an optical body with diffusion reflectivity according to claim 15 , further comprising the step of forming a random concave-convex surface in a master surface,

wherein, in forming the first optical layer, the random concave-convex surface in the master surface is transferred to a material of the first optical layer, thereby forming the first optical layer having the random concave-convex surface.

17. The method for manufacturing an optical body with diffusion reflectivity according to claim 16 , wherein, in forming the random concave-convex shape in the master surface, the random concave-convex surface is formed in the master surface by a sand blasting method, a laser interference method, or a method utilizing photolithography and etching.

18. A method for manufacturing an optical body with diffusion reflectivity, comprising:

forming a first optical layer having a random concave-convex surface;

forming a reflecting layer on the concave-convex surface; and

forming a second optical layer on the reflecting layer to embed so as to fill the concave-convex surface;

wherein the reflecting layer is a semi-transmissive layer for diffusely reflecting part of incident light and transmitting the remaining light therethrough, and

wherein a value of transmission image clarity for the light at wavelengths transmitting through the optical body is not smaller than 50 when measured in conformity with JIS K-7105 using an optical comb with a comb width of 0.5 mm.