| 摘要 |
PURPOSE: A ROM playing device of an HDDS(Holographic Digital Data Storage) system is provided to convert reference beams into parallel beams by using a mobile lens, and to exactly perform a focusing control by adding a cylindrical lens, thereby easily carrying out a tracking servo. CONSTITUTION: Reference beams(S1) of a wavelength which can be most efficiently used in a disk for an HDDS are incident on a disk(100), then reflected and incident on the first lens, that is, a mobile lens (200). The first lens(200) forms parallel beams while dynamically moving, and enables the parallel beams to be incident on the second lens(300). The second lens(300) transmits the incident parallel beams at certain angle, so that they cross at the center of a hole within an aperture(400), and the beams can be incident on the third lens(500). The third lens(500) transmits the incident beams at certain angle, and enables the beams to be incident on a cylindrical lens(600). The cylindrical lens(600) accurately focuses the beams transmitted through the third lens(500) such that the focused beams can be incident on a photo detector(S2). |
