In an exposure head of the invention, plural first micro-focusing elements
are arranged in a first microlens array so as to correspond to plural
micromirrors in a DMD. An aperture array that includes plural apertures
arranged so as to respectively correspond to the plural first
micro-focusing elements is disposed. The apertures allow only main
portions of Fraunhofer diffraction images to be transmitted therethrough.
The main portions of the Fraunhofer diffraction images transmitted
through the apertures are imaged on an exposure plane by second
micro-focusing elements of a second microlens array. According to the
exposure head of the invention, cross-talk light and scattered light can
be effectively reduced, and beam diameters of beam spots projected on the
exposure plane through the apertures can be adjusted to a required size.