Patent ID: 8421834

Claim:
An exposure device for engraving an image on a surface of a recording medium by scanning and exposing the recording medium with a light beam emitted from an exposure head, wherein the exposure head comprises: a light source that emits a first light beam, an exposure lens for causing the first light beam emitted from the light source to form an image on or close to the surface of the recording medium, and a direction changer disposed in at least one location of upstream of the exposure lens in a travel direction of the first light beam, downstream of the exposure lens in the travel direction of the first light beam and inside of the exposure lens on an optical path of a second light beam forming a part of the first light beam and having a numerical aperture higher than a given numerical aperture to change a travel direction of the second light beam in such a manner as to prevent the second light beam from affecting a process of engraving the image on the surface of the recording medium, wherein the light source is at least one group of optical fiber ends comprising arrayed optical fiber ends each of which emits the first light beam, wherein the exposure lens causes the first light beams emitted from the at least one group of optical fiber ends to form an image on or close to the surface of the recording medium, and wherein the direction changer is one of a refraction element for refracting the second light beam to change the direction of the second light beam, and a diffraction element for diffracting the second light beam to change the direction of the second light beam.