An illumination obscurement device for controlling the obscurement of illumination
from a light source which is optimized for use with a rectangular, arrayed, selective
reflection device. In a preferred embodiment, a rotatable shutter with three positions
is placed between a light source and a DMD. The first position of the shutter is
a mask, preferably an out of focus circle. This out of focus circle creates a circular
mask and changes any unwanted dim reflection to a circular shape. The second position
of the shutter is completely open, allowing substantially all the light to pass.
The third position of the shutter is completely closed, blocking substantially
all the light from passing. By controlling the penumbra illumination surrounding
the desired illumination, DMDs can be used in illumination devices without creating
undesirable rectangular penumbras.