Illumination device

FIG. 1 is a rear isometric view of an illumination device showing our new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a left side view thereof; and,

FIG. 5 is a right side view thereof.

The broken lines immediately adjacent to the shaded area represent unclaimed boundaries of the design. The broken lines showing the remainder of the illumination device are for environmental purposes only and form no part of the claimed design.