Illumination device and method for manufacturing same

An illumination device, comprising:

• a transparent substrate;
• a first electrode;
• an organic light-emitting unit provided between the transparent substrate and the first electrode, the organic light-emitting unit including an organic light-emitting layer, the organic light-emitting unit having a first major surface facing the first electrode;
• a second electrode provided between the transparent substrate and the organic light-emitting unit, the second electrode including,
• a conductive layer,
• a first interconnection electrically connected to the conductive layer and extending in a first direction parallel to the first major surface, the first interconnection having a conductivity higher than a conductivity of the conductive layer, the first interconnection overlapping the organic light-emitting unit as viewed from a normal direction perpendicular to the first major surface, and
• a second interconnection electrically connected to the conductive layer, being apart from the first interconnection and extending in a first direction, the second interconnection overlapping the organic light-emitting unit as viewed from the normal direction, the second interconnection having a conductivity higher than the conductivity of the conductive layer;
• an optical layer provided between the transparent substrate and the second electrode, the optical layer including,
• a low refractive index portion contacting the transparent substrate, the low refractive index portion overlapping the first interconnection and the second interconnection as viewed from the normal direction, and
• a high refractive index portion contacting the transparent substrate and contacting the low refractive index portion, a refractive index of the high refractive index portion being higher than a refractive index of the low refractive index portion and higher than a refractive index of the transparent substrate;
• and
• an insulating layer provided between the second electrode and the organic light-emitting unit, the insulating layer overlapping the first interconnection and the second interconnection as viewed from the normal direction, the insulating layer formed in part by using the first interconnection and the second interconnection as a mask to irradiate light onto an insulating film through the transparent substrate, the insulating film so formed serving as the insulating layer.