| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an objective optical device permitting to correct a spherical aberration or the like caused by differences of protective layer thickness among a high density optical disk, a DVD, and a CD by a phase structure function, permitting to obtain a high light utilization factor in any of the wavelength areas in the vicinity of 400nm, 650nm, and 780nm, and further having an excellent temperature characteristic, and also to provide an optical pickup device comprising this objective optical device, and an optical disk driving device mounted with this optical pickup device. <P>SOLUTION: The objective optical device of this invention comprises: a 1st phase structure for compensating for degradation of a condensing spot forming performance to an information recording surface of a 1st optical information recording medium produced by variation in temperature; a 2nd phase structure for offsetting the spherical aberration based on a difference in protective substrate thickness or an operating wavelength difference between the 1st optical information recording medium and the 2nd optical information recording medium; and a 3rd phase structure for offsetting the spherical aberration based on a difference in protective substrate thickness between the 1st optical information recording medium and the 3rd optical information recording medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
