| 摘要 |
PURPOSE:To provide an optical scanner for which a hologram is used and with which the deviation of scanning lines by eccentricity are decreased over the entire part of the scanning lines. CONSTITUTION:The radial position where the change rate of the spatial frequency of interference fringes is 0 is r0 in the central part 31 of a hologram facet 12 and an incident laser beam 18 is made incident on the side outer by dr than this position. The change rate of the spatial frequency of the interference fringes attains O in regions 35, 36 when the incident laser beam 18 moves the hologram facet 12 in accordance with the rotation of a hologram disk and, therefore, the deviation of the scanning lines by the eccentricity in this position is minimized. The deviation of the scanning line by the eccentricity increases in the central part 31 and at the ends 32, 33, but the max. value of the deviation over the entire part of the scanning lines is suppressed to a smaller level. |
