Optical element, window material, fitting, solar shading device, and building

1. An optical element comprising:

an optical layer having a concavo-convex surface formed on one surface thereof; and

a wavelength-selective reflection layer formed on the concavo-convex surface,

wherein:

the wavelength-selective reflection layer directionally reflects a light ray having a specific wavelength band, while transmitting light rays having wavelength bands other than the specific wavelength band,

the concavo-convex surface is provided with a plurality of first structural elements that are extended in a first direction within the surface of the optical layer and a plurality of second structural elements having a width of W 2 and that are extended in a second direction within the surface of the optical layer, and located so as to be spaced apart from one another, with the first direction and the second direction intersecting with each other,

the first structural elements have an first apex angle made by a first inclined surface and second inclined surface,

the second structural elements have a second apex angle made by a third inclined surface and fourth inclined surface,

supposing that a pitch of the second structural elements is P 2 , the pitch P 2 is 10*W 2 or more,

the wavelength-selective reflection layer is covered entirely with a resin,

the second structural elements each have an R-share on an apex portion thereof, and

a difference between angles of inclined surfaces of the first structural elements and the second structural elements is set in a range of ±15° or less.

2. The optical element according to claim 1 , wherein the optical layer has a belt-like or rectangular shape provided with a width direction and a longitudinal direction, with the first direction serving as the width direction of the optical layer and the second direction serving as the longitudinal direction of the optical layer.

3. The optical element according to claim 1 , wherein the optical layer has a rectangular shape with two pairs of opposed sides, with the first direction corresponding to an extending direction of one of the two pairs of sides and the second direction corresponding to an extending direction of the other of the two pairs of sides.

4. The optical element according to claim 1 , wherein the second structural element has an inclination of 65° or less.

5. The optical element according to claim 1 , further comprising:

an optical layer formed on the wavelength-selective reflection layer in a manner so as to bury the concavo-convex surface.

6. The optical element according to claim 1 , wherein an angle of intersection of the first direction and the second direction is orthogonal or substantially orthogonal.

7. The optical element according to claim 1 , wherein an angle of intersection of the first direction and the second direction is not orthogonal.

8. A window material comprising: an optical element according to claim 1 .

9. The window material according to claim 8 , wherein the optical element is installed such that an angle of intersection of a ridge line direction of the first structural element and a height direction of a building is orthogonal or substantially orthogonal.

10. A fitting comprising: an optical element according to claim 1 installed in a lighting unit.

11. A solar shading device comprising:

one or a plurality of solar shading members for shading solar light,

wherein the solar shading member is provided with an optical element according to claim 1 .

12. A building comprising: an optical element according to claim 1 .

13. The optical element according to claim 1 , wherein the light ray having a specific wavelength band is one portion of near infrared rays in solar light rays, and the light rays having wavelength bands other than the specific wavelength band are solar light rays other than the portion of near infrared rays.