| 摘要 |
PURPOSE:To obtain an information recording and reproducing device capable of easily re-writing information with the use of a high density recording medium by giving at least two types of crystal structures in the solid state and using a recording medium employing metal or alloy holding the crystal structure inherent to one temperature area in the other one. CONSTITUTION:The recording medium has at least two types of crystal structures in the solid state, holds the crystal structure inherent to one temperature area in the other one, and/or composed of the metal or alloy causing different volume changes in the crystal state. Assuming that a semiconductor laser 12 used for recording and reproducing and semiconductor lasers for erasure are symbol numbers 12, 13 and 14, respectively, a parallel light beam (i) is direction-changed by 90 deg. by means of an optical synthesizer, and an approximately circular optical spot is formed in the center of the recording line of a disk through almost the center of an object lens 5. On the other hand, parallel light beams (j) and (k) advance in the same direction of the optical synthesizer 33, and take such a path that the optical spot can be formed at a position deviated by a fine distance DELTAl with respect to the recording line of the disk. |
