An imaging optical instrument causes light emitted from a plurality of light
sources
arranged adjacent an object to image on recording surfaces of a photosensitive
or thermosensitive material. The optical instrument includes a two-sided telecentric
optical system having a first lens disposed adjacent an entrance end of a lens
barrel, and a second lens disposed adjacent an exit end of the lens barrel, and
an aperture stop disposed adjacent a meeting point of a rearward focus of the first
lens and a forward focus of the second lens. The aperture stop has an aperture
formed centrally thereof for allowing passage of beams that should contribute to
image formation, and a refracting portion surrounding the aperture for refracting
beams that should be intercepted and causing these beams to leave the lens barrel
from the exit end thereof.
