Illumination device having a lenticular lens sheet that is formed in a concave manner having a plano-convex cylindrical convex surface with a light source disposed within the convex surface

An illumination device comprising:

• a lenticular lens sheet that is acquired by arranging a plurality of plano-convex cylindrical lenses which extends in a first direction in a second direction perpendicular to the first direction, the lenticular lens sheet being curved in the first direction and having a convex surface of the plano-convex cylindrical lenses formed in a concave shape;
• and
• a light source that is disposed inside the convex surface of the plano-convex cylindrical lenses,
• wherein in a case where components acquired by reflecting light rays emitted from the light source from the convex surface include reflection components incident on left and right eyes of an observer positioned opposite to the lenticular lens with respect to the light source, bright points at which the reflection components are reflected from the convex surface form line-shaped light rays along the second direction.