Optical device, method for manufacturing the same and display device

An optical device comprising:

• a substrate having a three-dimensionally random concave-convex shape on a surface thereof;
• and
• a hard coat layer formed on the substrate, wherein
• a projection height with the maximum frequency on the hard coat layer surface falls within a range of 0.1 μm or more and not more than 5 μm;
• projections larger than the projection height with the maximum frequency on the hard coat layer surface have a height falling within +1 μm from a central value of the projection height with the maximum frequency;
• and
• a length RSm in a lateral direction of concaves and convexes on the hard coat layer surface is 55 μm or more and not more than 500 μm.

A display device comprising an optical device the optical device including:

• a substrate having a three-dimensionally random concave-convex shape on a surface thereof;
• and
• a hard coat layer formed on the substrate, wherein
• a projection height with the maximum frequency on the hard coat layer surface falls within a range of 0.1 μm or more and not more than 5 μm;
• projections larger than the projection height with the maximum frequency on the hard coat layer surface have a height falling within +1 μm from a central value of the projection height with the maximum frequency;
• and
• a length RSm in a lateral direction of concaves and convexes on the hard coat layer surface is 55 μm or more and not more than 500 μm.

A method for manufacturing an optical device, the method comprising:

• preparing a master disc having a three-dimensionally random concave-convex shape on the surface thereof by blasting;
• transferring the concave-convex shape of the master disc onto a substrate;
• and
• forming a hard coat layer on the substrate by coating a hard coat coating material on a surface of the substrate on which the concave-convex shape is formed and curing the hard coat coating material, wherein
• a projection height with the maximum frequency on the substrate surface falls within a range of 1.5 μm or more and not more than 10 μm;
• projections larger than the projection height with the maximum frequency on the substrate surface have a height falling within +3 μm from a central value of the projection height with the maximum frequency;
• and
• a length RSm in a lateral direction of concaves and convexes on the substrate surface is 55 μm or more and not more than 500 μm.