| 摘要 |
An exposure device engraves an image on the surface of a recording medium by scanning and exposing the recording medium with a light beam emitted from an exposure head. The exposure head comprises a light source for emitting a light beam, an exposure lens for causing the light beam to form an image on or close to the surface of the recording medium, a direction changer disposed upstream or downstream of the exposure lens in the direction in which the light beam travels, and/or inside of the exposure lens on the optical path of a light beam having a numerical aperture higher than a given numerical aperture to change the direction of the light beam having a numerical aperture higher than a given numerical aperture in such a manner as not to affect the process of engraving an image on a surface of the recording medium.
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