OPTICAL INTEGRATOR, ILLUMINATION UNIT, TRANSMISSION OPTICAL SYSTEM, ILLUMINATION OPTICAL SYSTEM, EXPOSURE DEVICE, AND DEVICE MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a transmission optical system capable of stably guiding a light flux having substantially uniform intensity distribution to a spatial light modulator even when output distribution of a power source is changed.SOLUTION: A transmission optical system comprises: an optical integrator including a plurality of wavefront splitting elements arranged in parallel; and a condenser optical system for superimposing a plurality of light fluxes wavefront-split by the optical integrator on an action face of the spatial light modulator. Each of the wavefront splitting elements includes: a first optical surface of a cylindrical surface shape having a positive refractive power with respect to a first direction; a second optical surface of a cylindrical surface shape arranged at a back side of the first optical surface and having a positive refractive power with respect to a second direction; and a third optical surface arranged at a back side of the second optical surface, having a positive refractive power with respect to the first direction and having a positive refractive power with respect to the second direction. A focal distance of the optical integrator with respect to the first direction is larger than a focal distance with respect to the second direction.