| 摘要 |
PROBLEM TO BE SOLVED: To provide an information recording/reproducing device, in which the high recording density for a recording medium and the highly accurate tracking control are attainable, and also to provide an optical system and optical element suitable therefor. SOLUTION: A recording/reproducing light DL is converged on a minute opening 19H which is formed on a thin film 19 located at an almost center of a flat surface part 18U of an immersion lens SIL formed by a medium having the high refractive index, to generate a near-field light NP1 for the recording/ reproducing operation, then minute recording pits DP are formed on land part 20L. The size of the thin film 19 is made a little larger than that of a spot of the recording/reproducing light DL. Tracking light TL is totally reflected at the position where no thin film 19 exists in the flat surface part 18U, being the nearest position to the minute opening 19H. Then a tracking spot TS over the groove part 20G is made to be minute for generating a near-field light NP2 for tracking, and the recording/reproducing position becomes near to the tracking position in the recording medium 20, then the highly accurate tracking and the high density recording are attained. |
