| 摘要 |
A hologon scanning system which provides two sequential scans across an image plane per revolution of the hologon. The hologon is a disc having a single facet with a planar linear diffraction grating in a surface which is perpendicular to the axis of rotation of the disc and which is centered on the axis of rotation. An incident laser beam which preferably overfills the facet is diffracted and scanned by the rotation of the facet. The facet is preferably elliptical in shape with its major axis perpendicular to the facet grating lines. The diameter of the disc can be made only slightly larger than the profile of the incident beam on the disc so as to minimize inertia and enable the disc to be rotated at very high speeds without failure due to centrifugal force induced stress. Four sequential scans per revolution can be produced by using a pair of superimposed centered facets with their grating lines oriented orthogonally to each other. This monograting disc deflector provides a cost-effective scanner solution for high resolution, flat field imaging applications.
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