Photoelectric conversion device, imaging system, photoelectric conversion device designing method, and photoelectric conversion device manufacturing method

A photoelectric conversion device comprising:

• a plurality of photoelectric conversion units which are arranged in a semiconductor substrate;
• a first antireflection portion including a first insulation film which is arranged on the photoelectric conversion units and which has a first refractive index, and a second insulation film which is arranged on the first insulation film and which has a second refractive index;
• and
• a second antireflection portion including an element isolation portion which is arranged in the semiconductor substrate and which electrically isolates the plurality of photoelectric conversion units and which includes an insulator having a third refractive index, and a third insulation film which is thicker than the second insulation film and which is arranged on the element isolation portion and which has the second refractive index,
• wherein the first antireflection portion reduces reflection of light entering the photoelectric conversion units in the photoelectric conversion units, and
• the second antireflection portion reduces reflection of light entering the element isolation portion in the element isolation portion.