| 摘要 |
PROBLEM TO BE SOLVED: To provide a simple, small and inexpensive which can perform stable recording and reproducing operation for every recording layer set in the depth direction. SOLUTION: This optical pickup device is provided with 1st and 2nd light sources 12 and 21 which radiate 1st and 2nd light beams 10 and 20 of different wavelengths, objective lenses 17a and 17b which are selectively placed on a common optical path of both beams 10 and 20 and condense these beams in different spot spaces and an objective lens selection means which selects one of lenses 17a and 17b that is placed on the common optical path in accordance with the depth position of a desired recording layer 6 that is to be recorded and reproduced. Then the beam 10 is condensed on a guide track layer 2 via the objective lens that is placed on the common optical path and also the beam 20 is condensed on the desired layer 6. Thus, the information is optically recorded and reproduced on an information recording medium 1 which has the layer 2 and plural layers 6 in its depth direction. |
