Abstract: The illumination optical system includes an illumination light source and a spatial light modulator having a plurality of elements which reflect incident light from the illumination light source to form outgoing light and which flexibly switch a deflecting direction of a principal ray of the outgoing light between at least two directions including a first deflecting direction and a second deflecting direction, wherein a first angle between an incident direction of a principal ray of the incident light and the first deflecting direction is set to be approximately equal to a second angle between the first deflecting direction and the second deflecting direction and/or the first and second deflecting directions of the principal ray of the outgoing light inclines with reference to a normal line to an element array surface of the spatial light modulator. The image display apparatus and the image exposure apparatus have the above illumination optical system.

Abstract: The illumination optical system includes an illumination light source and a spatial light modulator having a plurality of elements which reflect incident light from the illumination light source to form outgoing light and which flexibly switch a deflecting direction of a principal ray of the outgoing light between at least two directions including a first deflecting direction and a second deflecting direction, wherein a first angle between an incident direction of a principal ray of the incident light and the first deflecting direction is set to be approximately equal to a second angle between the first deflecting direction and the second deflecting direction and/or the first and second deflecting directions of the principal ray of the outgoing light inclines with reference to a normal line to an element array surface of the spatial light modulator. The image display apparatus and the image exposure apparatus have the above illumination optical system.