| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an objective lens for an optical pickup of high NA which has a reduced weight by securing sufficient lens back while satisfactorily correcting on-axis characteristics and off-axis characteristics. <P>SOLUTION: The objective lens for the optical pickup (10), which has a numerical aperture (NA) of 0.8-0.9, uses a light source which emits a laser beam of wavelength of 420 nm or below, and condenses the luminous flux emitted from the light source on the information recording surface of an optical information recording medium, is a single lens of an aspheric surface shape wherein both a first face (11) and a second face (12) are continued in order from the light source side, and satisfies the following formulae (1) to (3): formula (1) OSCpv<0.020; formula (2) 0.900≤t/f<1.100; and formula (3) 1.520≤n≤1.720. <P>COPYRIGHT: (C)2011,JPO&INPIT |
