Abstract: An illumination optical system include a first lens array including multiple lens cells that split a light beam emitted from a light source into multiple light beams, a second lens array including lens cells that the light beams split by the lens cells of the first lens array are incident thereon, and an optical element configured to illuminate an image display element by superposing light beams emerging from the second lens array on the image display element. At least one of the first lens array and the second lens array includes at least two lens cells each having a curved surface that is formed so as to be continuous with a curved surface of an adjacent lens cell, the at least two lens cells being decentered, and at least two lens cells of the first lens array have different radii of curvature.

Abstract: An image display apparatus includes an image display element configured to display an image by controlling a polarization state of a polarized light beam. An illumination optical system guides the polarized light beam to the image display element. A polarizing beam splitter disposed between the illumination optical system and the image display element selectively splits polarization of incident light. A projection optical system projects the image displayed by the image display element onto a projection plane. The positional relationship between the polarizing beam splitter and an optical axis of the projection optical system is properly set.