Optical sheet, image source unit and image display device

1. A laminate having a plurality of layers, the laminate comprising:

a substrate layer including a rough surface on an output side of the laminate; and

an optical function layer that is layered on a surface of the substrate layer opposite the rough surface, and has a plurality of light transmission parts which are arranged in a row along a surface of the substrate layer at predetermined intervals, the light transmission parts being light-transmissive, each of the light transmission parts having a predetermined cross section in a layer thickness direction, the light transmission parts extending in a direction across the optical function layer, and light absorption parts in a row, each of which is arranged between adjacent ones of the light transmission parts so as to be light-absorptive, the light absorption parts each having a second predetermined cross section in a layer thickness direction, the light absorption parts extending in said direction across the optical function layer; and

wherein on a cross section of the optical function layer in a layer thickness direction, a cross-sectional area of one of the light transmission parts to a total cross-sectional area of one of the light transmission parts and one of the light absorption parts which are adjacent to each other is 78.2% to 88.5%, and

when irradiation light inclining at 45° from a normal line of the optical function layer is irradiated in a direction of alternately aligning the light transmission parts and the light absorbing parts of the optical function layer, a light trapping box is arranged on an opposite side of the laminate, and omnidirectional light when 45° specular reflected light is excluded from reflected light of this irradiation light is defined as an optical diffuse reflectance, an optical diffuse reflectance on the light output surface side of the laminate is 1.9% to 3.5%.

2. The laminate according to claim 1 , wherein an optical diffuse reflectance on a light input surface side of the laminate is 2.5% to 5.0%.

3. A laminate having a plurality of layers, the laminate comprising:

a substrate layer;

an optical function layer that is layered on one surface of the substrate layer, and has a plurality of light transmission parts which are arranged in a row along a surface of the substrate layer at predetermined intervals, the light transmission parts being light-transmissive, each of the light transmission parts having a predetermined cross section in a layer thickness direction, the light transmission parts extending in a direction across the optical function layer, and light absorption parts in a row, each of which is arranged between adjacent ones of the light transmission parts so as to be light-absorptive, the light absorption parts each having a second predetermined cross section in a layer thickness direction, the light absorption parts extending in said direction across the optical function layer; and

a reflective polarizing plate that is arranged on the optical function layer on a side opposite to the substrate layer,

wherein on a cross section of the optical function layer in a layer thickness direction, a cross-sectional area of one of the light transmission parts to a total cross-sectional area of one of the light transmission parts and one of the light absorption parts which are adjacent to each other is 78.2% to 88.5%, and

when irradiation light inclining at 45° from a normal line of the optical function layer is irradiated in a direction of alternately aligning the light transmission parts and the light absorbing parts of the optical function layer, a light trapping box is arranged on an opposite side of the laminate and omnidirectional light when 45° specular reflected light is excluded from reflected light of this irradiation light is defined as an optical diffuse reflectance, an optical diffuse reflectance on the light input surface side of the laminate is 8.2% to 9.7%, wherein the laminate has a rough surface on a side facing the irradiation light.

4. The laminate according to claim 1 , wherein the first predetermined cross section in the layer thickness direction is a trapezoid.

5. The laminate according to claim 3 , wherein the first predetermined cross section in the layer thickness direction is a trapezoid.

6. An image source unit comprising a liquid crystal panel that is arranged on a light output side of the laminate according to claim 1 .

7. An image source unit comprising a liquid crystal panel that is arranged on a light output side of the laminate according to claim 3 .

8. An image display device comprising:

a housing; and

the image source unit according to claim 6 which is arranged inside the housing.

9. An image display device comprising:

a housing; and

the image source unit according to claim 7 which is arranged inside the housing.

10. The laminate according to claim 1 , wherein the difference between a refractive index of each of the light transmission parts and a refractive index of each of the light absorption parts is no less than 0.05.

11. The laminate according to claim 3 , wherein the difference between a refractive index of each of the light transmission parts and a refractive index of each of the light absorption parts is no less than 0.05.

12. The laminate according to claim 1 , wherein a proportion of opening of the optical function layer is at least 71.8%.

13. The laminate according to claim 3 , wherein a proportion of opening of the optical function layer is at least 71.8%.

14. The laminate according to claim 1 , wherein the rough surface has an arithmetic mean roughness of between 0.1 μm to 0.2 μm as measured according to JIS B 0601.

15. The laminate according to claim 3 , wherein the rough surface has an arithmetic mean roughness of between 0.1 μm to 0.2 μm as measured according to JIS B 0601.