| 摘要 |
PURPOSE:To scan linearly a reproducing image on an image forming surface by making the incident angle of reference light and reproducing light different from each other as a hologram disk rotates, and varying the diffraction angle of diffracted light by utilizing its angle difference. CONSTITUTION:As for an object light source 22 which is used when preparing a hologram, a laser beam converged to the center of a scanning line obtained on an image forming surface 4 is used, and as for a reference light source 20, the divergence point light source of the same wavelength as the object light source 22 is used, and they are installed at a prescribed position. Both light sources 22, 20 are installed so that an incident angle to a hologram disk 3 of an optical beam emitted from said source becomes other angle than 0 deg. in the scanning center, and an interference fringe is recorded on the hologram 3 by light from these respective light sources. As for a reproducing light source (incident angle thetai) 21 which is used at the time of reproducing (scanning), divergence point light source which has the same wavelength as the reference light source 20 and is installed at the same position is used, so that an optical spot which is smaller than an optical spot by the reference light source 20 is irradiated onto the hologram 3. |
