Abstract: An optical scanning unit with a rotatable hologram disc, including a light source, a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract a beam emitted from the light source by multiple steps, a reflecting member that reflects the beam emitted from the light source and diffracted by one of the holograms into another hologram, and a fixed hologram correcting the diffracted beam incident through the rotatable hologram disc to focus it on a scanning object. In the optical scanning unit, the light passes through the plurality of holograms formed along a radial direction of the rotatable hologram disc so that a scan width can be extended without reducing a scan speed of the optical scanning unit.

Abstract: An optical scanning unit with a rotatable hologram disc, including a light source, a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract a beam emitted from the light source by multiple steps, a reflecting member that reflects the beam emitted from the light source and diffracted by one of the holograms into another hologram, and a fixed hologram correcting the diffracted beam incident through the rotatable hologram disc to focus it on a scanning object. In the optical scanning unit, the light passes through the plurality of holograms formed along a radial direction of the rotatable hologram disc so that a scan width can be extended without reducing a scan speed of the optical scanning unit.